1 files changed, 1276 insertions, 0 deletions

diff --git a/contrib/SDL-3.2.8/src/render/gpu/SDL_render_gpu.c b/contrib/SDL-3.2.8/src/render/gpu/SDL_render_gpu.c
new file mode 100644
index 0000000..73c1dbe
--- /dev/null
+++ b/contrib/SDL-3.2.8/src/render/gpu/SDL_render_gpu.c
@@ -0,0 +1,1276 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_internal.h"
+
+#ifdef SDL_VIDEO_RENDER_GPU
+
+#include "../../video/SDL_pixels_c.h"
+#include "../SDL_d3dmath.h"
+#include "../SDL_sysrender.h"
+#include "SDL_gpu_util.h"
+#include "SDL_pipeline_gpu.h"
+#include "SDL_shaders_gpu.h"
+
+typedef struct GPU_ShaderUniformData
+{
+    Float4X4 mvp;
+    SDL_FColor color;
+    float texture_size[2];
+} GPU_ShaderUniformData;
+
+typedef struct GPU_RenderData
+{
+    SDL_GPUDevice *device;
+    GPU_Shaders shaders;
+    GPU_PipelineCache pipeline_cache;
+
+    struct
+    {
+        SDL_GPUTexture *texture;
+        SDL_GPUTextureFormat format;
+        Uint32 width;
+        Uint32 height;
+    } backbuffer;
+
+    struct
+    {
+        SDL_GPUSwapchainComposition composition;
+        SDL_GPUPresentMode present_mode;
+    } swapchain;
+
+    struct
+    {
+        SDL_GPUTransferBuffer *transfer_buf;
+        SDL_GPUBuffer *buffer;
+        Uint32 buffer_size;
+    } vertices;
+
+    struct
+    {
+        SDL_GPURenderPass *render_pass;
+        SDL_Texture *render_target;
+        SDL_GPUCommandBuffer *command_buffer;
+        SDL_GPUColorTargetInfo color_attachment;
+        SDL_GPUViewport viewport;
+        SDL_Rect scissor;
+        SDL_FColor draw_color;
+        bool scissor_enabled;
+        bool scissor_was_enabled;
+        GPU_ShaderUniformData shader_data;
+    } state;
+
+    SDL_GPUSampler *samplers[2][2];
+} GPU_RenderData;
+
+typedef struct GPU_TextureData
+{
+    SDL_GPUTexture *texture;
+    SDL_GPUTextureFormat format;
+    GPU_FragmentShaderID shader;
+    void *pixels;
+    int pitch;
+    SDL_Rect locked_rect;
+} GPU_TextureData;
+
+static bool GPU_SupportsBlendMode(SDL_Renderer *renderer, SDL_BlendMode blendMode)
+{
+    SDL_BlendFactor srcColorFactor = SDL_GetBlendModeSrcColorFactor(blendMode);
+    SDL_BlendFactor srcAlphaFactor = SDL_GetBlendModeSrcAlphaFactor(blendMode);
+    SDL_BlendOperation colorOperation = SDL_GetBlendModeColorOperation(blendMode);
+    SDL_BlendFactor dstColorFactor = SDL_GetBlendModeDstColorFactor(blendMode);
+    SDL_BlendFactor dstAlphaFactor = SDL_GetBlendModeDstAlphaFactor(blendMode);
+    SDL_BlendOperation alphaOperation = SDL_GetBlendModeAlphaOperation(blendMode);
+
+    if (GPU_ConvertBlendFactor(srcColorFactor) == SDL_GPU_BLENDFACTOR_INVALID ||
+        GPU_ConvertBlendFactor(srcAlphaFactor) == SDL_GPU_BLENDFACTOR_INVALID ||
+        GPU_ConvertBlendOperation(colorOperation) == SDL_GPU_BLENDOP_INVALID ||
+        GPU_ConvertBlendFactor(dstColorFactor) == SDL_GPU_BLENDFACTOR_INVALID ||
+        GPU_ConvertBlendFactor(dstAlphaFactor) == SDL_GPU_BLENDFACTOR_INVALID ||
+        GPU_ConvertBlendOperation(alphaOperation) == SDL_GPU_BLENDOP_INVALID) {
+        return false;
+    }
+
+    return true;
+}
+
+static SDL_GPUTextureFormat PixFormatToTexFormat(SDL_PixelFormat pixel_format)
+{
+    switch (pixel_format) {
+    case SDL_PIXELFORMAT_BGRA32:
+    case SDL_PIXELFORMAT_BGRX32:
+        return SDL_GPU_TEXTUREFORMAT_B8G8R8A8_UNORM;
+    case SDL_PIXELFORMAT_RGBA32:
+    case SDL_PIXELFORMAT_RGBX32:
+        return SDL_GPU_TEXTUREFORMAT_R8G8B8A8_UNORM;
+
+    // YUV TODO
+    case SDL_PIXELFORMAT_YV12:
+    case SDL_PIXELFORMAT_IYUV:
+    case SDL_PIXELFORMAT_NV12:
+    case SDL_PIXELFORMAT_NV21:
+    case SDL_PIXELFORMAT_UYVY:
+    default:
+        return SDL_GPU_TEXTUREFORMAT_INVALID;
+    }
+}
+
+static SDL_PixelFormat TexFormatToPixFormat(SDL_GPUTextureFormat tex_format)
+{
+    switch (tex_format) {
+    case SDL_GPU_TEXTUREFORMAT_R8G8B8A8_UNORM:
+        return SDL_PIXELFORMAT_RGBA32;
+    case SDL_GPU_TEXTUREFORMAT_B8G8R8A8_UNORM:
+        return SDL_PIXELFORMAT_BGRA32;
+    case SDL_GPU_TEXTUREFORMAT_B5G6R5_UNORM:
+        return SDL_PIXELFORMAT_BGR565;
+    case SDL_GPU_TEXTUREFORMAT_B5G5R5A1_UNORM:
+        return SDL_PIXELFORMAT_BGRA5551;
+    case SDL_GPU_TEXTUREFORMAT_B4G4R4A4_UNORM:
+        return SDL_PIXELFORMAT_BGRA4444;
+    case SDL_GPU_TEXTUREFORMAT_R10G10B10A2_UNORM:
+        return SDL_PIXELFORMAT_ABGR2101010;
+    case SDL_GPU_TEXTUREFORMAT_R16G16B16A16_UNORM:
+        return SDL_PIXELFORMAT_RGBA64;
+    case SDL_GPU_TEXTUREFORMAT_R8G8B8A8_SNORM:
+        return SDL_PIXELFORMAT_RGBA32;
+    case SDL_GPU_TEXTUREFORMAT_R16G16B16A16_FLOAT:
+        return SDL_PIXELFORMAT_RGBA64_FLOAT;
+    case SDL_GPU_TEXTUREFORMAT_R32G32B32A32_FLOAT:
+        return SDL_PIXELFORMAT_RGBA128_FLOAT;
+    case SDL_GPU_TEXTUREFORMAT_R8G8B8A8_UINT:
+        return SDL_PIXELFORMAT_RGBA32;
+    case SDL_GPU_TEXTUREFORMAT_R16G16B16A16_UINT:
+        return SDL_PIXELFORMAT_RGBA64;
+    case SDL_GPU_TEXTUREFORMAT_R8G8B8A8_UNORM_SRGB:
+        return SDL_PIXELFORMAT_RGBA32;
+    case SDL_GPU_TEXTUREFORMAT_B8G8R8A8_UNORM_SRGB:
+        return SDL_PIXELFORMAT_BGRA32;
+    default:
+        return SDL_PIXELFORMAT_UNKNOWN;
+    }
+}
+
+static bool GPU_CreateTexture(SDL_Renderer *renderer, SDL_Texture *texture, SDL_PropertiesID create_props)
+{
+    GPU_RenderData *renderdata = (GPU_RenderData *)renderer->internal;
+    GPU_TextureData *data;
+    SDL_GPUTextureFormat format;
+    SDL_GPUTextureUsageFlags usage = SDL_GPU_TEXTUREUSAGE_SAMPLER;
+
+    format = PixFormatToTexFormat(texture->format);
+
+    if (format == SDL_GPU_TEXTUREFORMAT_INVALID) {
+        return SDL_SetError("Texture format %s not supported by SDL_GPU",
+                            SDL_GetPixelFormatName(texture->format));
+    }
+
+    data = (GPU_TextureData *)SDL_calloc(1, sizeof(*data));
+    if (!data) {
+        return false;
+    }
+
+    if (texture->access == SDL_TEXTUREACCESS_STREAMING) {
+        size_t size;
+        data->pitch = texture->w * SDL_BYTESPERPIXEL(texture->format);
+        size = (size_t)texture->h * data->pitch;
+        if (texture->format == SDL_PIXELFORMAT_YV12 ||
+            texture->format == SDL_PIXELFORMAT_IYUV) {
+            // Need to add size for the U and V planes
+            size += 2 * ((texture->h + 1) / 2) * ((data->pitch + 1) / 2);
+        }
+        if (texture->format == SDL_PIXELFORMAT_NV12 ||
+            texture->format == SDL_PIXELFORMAT_NV21) {
+            // Need to add size for the U/V plane
+            size += 2 * ((texture->h + 1) / 2) * ((data->pitch + 1) / 2);
+        }
+        data->pixels = SDL_calloc(1, size);
+        if (!data->pixels) {
+            SDL_free(data);
+            return false;
+        }
+
+        // TODO allocate a persistent transfer buffer
+    }
+
+    if (texture->access == SDL_TEXTUREACCESS_TARGET) {
+        usage |= SDL_GPU_TEXTUREUSAGE_COLOR_TARGET;
+    }
+
+    texture->internal = data;
+    SDL_GPUTextureCreateInfo tci;
+    SDL_zero(tci);
+    tci.format = format;
+    tci.layer_count_or_depth = 1;
+    tci.num_levels = 1;
+    tci.usage = usage;
+    tci.width = texture->w;
+    tci.height = texture->h;
+    tci.sample_count = SDL_GPU_SAMPLECOUNT_1;
+
+    data->format = format;
+    data->texture = SDL_CreateGPUTexture(renderdata->device, &tci);
+
+    if (!data->texture) {
+        return false;
+    }
+
+    if (texture->format == SDL_PIXELFORMAT_RGBA32 || texture->format == SDL_PIXELFORMAT_BGRA32) {
+        data->shader = FRAG_SHADER_TEXTURE_RGBA;
+    } else {
+        data->shader = FRAG_SHADER_TEXTURE_RGB;
+    }
+
+    return true;
+}
+
+static bool GPU_UpdateTexture(SDL_Renderer *renderer, SDL_Texture *texture,
+                              const SDL_Rect *rect, const void *pixels, int pitch)
+{
+    GPU_RenderData *renderdata = (GPU_RenderData *)renderer->internal;
+    GPU_TextureData *data = (GPU_TextureData *)texture->internal;
+    const Uint32 texturebpp = SDL_BYTESPERPIXEL(texture->format);
+
+    size_t row_size, data_size;
+
+    if (!SDL_size_mul_check_overflow(rect->w, texturebpp, &row_size) ||
+        !SDL_size_mul_check_overflow(rect->h, row_size, &data_size)) {
+        return SDL_SetError("update size overflow");
+    }
+
+    SDL_GPUTransferBufferCreateInfo tbci;
+    SDL_zero(tbci);
+    tbci.size = (Uint32)data_size;
+    tbci.usage = SDL_GPU_TRANSFERBUFFERUSAGE_UPLOAD;
+
+    SDL_GPUTransferBuffer *tbuf = SDL_CreateGPUTransferBuffer(renderdata->device, &tbci);
+
+    if (tbuf == NULL) {
+        return false;
+    }
+
+    Uint8 *output = SDL_MapGPUTransferBuffer(renderdata->device, tbuf, false);
+
+    if ((size_t)pitch == row_size) {
+        SDL_memcpy(output, pixels, data_size);
+    } else {
+        // FIXME is negative pitch supposed to work?
+        // If not, maybe use SDL_GPUTextureTransferInfo::pixels_per_row instead of this
+        const Uint8 *input = pixels;
+
+        for (int i = 0; i < rect->h; ++i) {
+            SDL_memcpy(output, input, row_size);
+            output += row_size;
+            input += pitch;
+        }
+    }
+
+    SDL_UnmapGPUTransferBuffer(renderdata->device, tbuf);
+
+    SDL_GPUCommandBuffer *cbuf = renderdata->state.command_buffer;
+    SDL_GPUCopyPass *cpass = SDL_BeginGPUCopyPass(cbuf);
+
+    SDL_GPUTextureTransferInfo tex_src;
+    SDL_zero(tex_src);
+    tex_src.transfer_buffer = tbuf;
+    tex_src.rows_per_layer = rect->h;
+    tex_src.pixels_per_row = rect->w;
+
+    SDL_GPUTextureRegion tex_dst;
+    SDL_zero(tex_dst);
+    tex_dst.texture = data->texture;
+    tex_dst.x = rect->x;
+    tex_dst.y = rect->y;
+    tex_dst.w = rect->w;
+    tex_dst.h = rect->h;
+    tex_dst.d = 1;
+
+    SDL_UploadToGPUTexture(cpass, &tex_src, &tex_dst, false);
+    SDL_EndGPUCopyPass(cpass);
+    SDL_ReleaseGPUTransferBuffer(renderdata->device, tbuf);
+
+    return true;
+}
+
+static bool GPU_LockTexture(SDL_Renderer *renderer, SDL_Texture *texture,
+                            const SDL_Rect *rect, void **pixels, int *pitch)
+{
+    GPU_TextureData *data = (GPU_TextureData *)texture->internal;
+
+    data->locked_rect = *rect;
+    *pixels =
+        (void *)((Uint8 *)data->pixels + rect->y * data->pitch +
+                 rect->x * SDL_BYTESPERPIXEL(texture->format));
+    *pitch = data->pitch;
+    return true;
+}
+
+static void GPU_UnlockTexture(SDL_Renderer *renderer, SDL_Texture *texture)
+{
+    GPU_TextureData *data = (GPU_TextureData *)texture->internal;
+    const SDL_Rect *rect;
+    void *pixels;
+
+    rect = &data->locked_rect;
+    pixels =
+        (void *)((Uint8 *)data->pixels + rect->y * data->pitch +
+                 rect->x * SDL_BYTESPERPIXEL(texture->format));
+    GPU_UpdateTexture(renderer, texture, rect, pixels, data->pitch);
+}
+
+static void GPU_SetTextureScaleMode(SDL_Renderer *renderer, SDL_Texture *texture, SDL_ScaleMode scale_mode)
+{
+    // nothing to do in this backend.
+}
+
+static bool GPU_SetRenderTarget(SDL_Renderer *renderer, SDL_Texture *texture)
+{
+    GPU_RenderData *data = (GPU_RenderData *)renderer->internal;
+
+    data->state.render_target = texture;
+
+    return true;
+}
+
+static bool GPU_QueueNoOp(SDL_Renderer *renderer, SDL_RenderCommand *cmd)
+{
+    return true; // nothing to do in this backend.
+}
+
+static SDL_FColor GetDrawCmdColor(SDL_Renderer *renderer, SDL_RenderCommand *cmd)
+{
+    SDL_FColor color = cmd->data.color.color;
+
+    if (SDL_RenderingLinearSpace(renderer)) {
+        SDL_ConvertToLinear(&color);
+    }
+
+    color.r *= cmd->data.color.color_scale;
+    color.g *= cmd->data.color.color_scale;
+    color.b *= cmd->data.color.color_scale;
+
+    return color;
+}
+
+static bool GPU_QueueDrawPoints(SDL_Renderer *renderer, SDL_RenderCommand *cmd, const SDL_FPoint *points, int count)
+{
+    float *verts = (float *)SDL_AllocateRenderVertices(renderer, count * 2 * sizeof(float), 0, &cmd->data.draw.first);
+
+    if (!verts) {
+        return false;
+    }
+
+    cmd->data.draw.count = count;
+    for (int i = 0; i < count; i++) {
+        *(verts++) = 0.5f + points[i].x;
+        *(verts++) = 0.5f + points[i].y;
+    }
+
+    return true;
+}
+
+static bool GPU_QueueGeometry(SDL_Renderer *renderer, SDL_RenderCommand *cmd, SDL_Texture *texture,
+                              const float *xy, int xy_stride, const SDL_FColor *color, int color_stride, const float *uv, int uv_stride,
+                              int num_vertices, const void *indices, int num_indices, int size_indices,
+                              float scale_x, float scale_y)
+{
+    int i;
+    int count = indices ? num_indices : num_vertices;
+    float *verts;
+    size_t sz = 2 * sizeof(float) + 4 * sizeof(float) + (texture ? 2 : 0) * sizeof(float);
+    const float color_scale = cmd->data.draw.color_scale;
+    bool convert_color = SDL_RenderingLinearSpace(renderer);
+
+    verts = (float *)SDL_AllocateRenderVertices(renderer, count * sz, 0, &cmd->data.draw.first);
+    if (!verts) {
+        return false;
+    }
+
+    cmd->data.draw.count = count;
+    size_indices = indices ? size_indices : 0;
+
+    for (i = 0; i < count; i++) {
+        int j;
+        float *xy_;
+        SDL_FColor col_;
+        if (size_indices == 4) {
+            j = ((const Uint32 *)indices)[i];
+        } else if (size_indices == 2) {
+            j = ((const Uint16 *)indices)[i];
+        } else if (size_indices == 1) {
+            j = ((const Uint8 *)indices)[i];
+        } else {
+            j = i;
+        }
+
+        xy_ = (float *)((char *)xy + j * xy_stride);
+
+        *(verts++) = xy_[0] * scale_x;
+        *(verts++) = xy_[1] * scale_y;
+
+        col_ = *(SDL_FColor *)((char *)color + j * color_stride);
+        if (convert_color) {
+            SDL_ConvertToLinear(&col_);
+        }
+
+        // FIXME: The Vulkan backend doesn't multiply by color_scale. GL does. I'm not sure which one is wrong.
+        // ANSWER: The color scale should be applied in linear space when using the scRGB colorspace. This is done in shaders in the Vulkan backend.
+        *(verts++) = col_.r * color_scale;
+        *(verts++) = col_.g * color_scale;
+        *(verts++) = col_.b * color_scale;
+        *(verts++) = col_.a;
+
+        if (texture) {
+            float *uv_ = (float *)((char *)uv + j * uv_stride);
+            *(verts++) = uv_[0] * texture->w;
+            *(verts++) = uv_[1] * texture->h;
+        }
+    }
+    return true;
+}
+
+static void GPU_InvalidateCachedState(SDL_Renderer *renderer)
+{
+    GPU_RenderData *data = (GPU_RenderData *)renderer->internal;
+
+    data->state.render_target = NULL;
+    data->state.scissor_enabled = false;
+}
+
+static SDL_GPURenderPass *RestartRenderPass(GPU_RenderData *data)
+{
+    if (data->state.render_pass) {
+        SDL_EndGPURenderPass(data->state.render_pass);
+    }
+
+    data->state.render_pass = SDL_BeginGPURenderPass(
+        data->state.command_buffer, &data->state.color_attachment, 1, NULL);
+
+    // *** FIXME ***
+    // This is busted. We should be able to know which load op to use.
+    // LOAD is incorrect behavior most of the time, unless we had to break a render pass.
+    // -cosmonaut
+    data->state.color_attachment.load_op = SDL_GPU_LOADOP_LOAD;
+    data->state.scissor_was_enabled = false;
+
+    return data->state.render_pass;
+}
+
+static void PushUniforms(GPU_RenderData *data, SDL_RenderCommand *cmd)
+{
+    GPU_ShaderUniformData uniforms;
+    SDL_zero(uniforms);
+    uniforms.mvp.m[0][0] = 2.0f / data->state.viewport.w;
+    uniforms.mvp.m[1][1] = -2.0f / data->state.viewport.h;
+    uniforms.mvp.m[2][2] = 1.0f;
+    uniforms.mvp.m[3][0] = -1.0f;
+    uniforms.mvp.m[3][1] = 1.0f;
+    uniforms.mvp.m[3][3] = 1.0f;
+
+    uniforms.color = data->state.draw_color;
+
+    if (cmd->data.draw.texture) {
+        uniforms.texture_size[0] = cmd->data.draw.texture->w;
+        uniforms.texture_size[1] = cmd->data.draw.texture->h;
+    }
+
+    SDL_PushGPUVertexUniformData(data->state.command_buffer, 0, &uniforms, sizeof(uniforms));
+}
+
+static SDL_GPUSampler **SamplerPointer(
+    GPU_RenderData *data, SDL_TextureAddressMode address_mode, SDL_ScaleMode scale_mode)
+{
+    return &data->samplers[scale_mode][address_mode - 1];
+}
+
+static void SetViewportAndScissor(GPU_RenderData *data)
+{
+    SDL_SetGPUViewport(data->state.render_pass, &data->state.viewport);
+
+    if (data->state.scissor_enabled) {
+        SDL_SetGPUScissor(data->state.render_pass, &data->state.scissor);
+        data->state.scissor_was_enabled = true;
+    } else if (data->state.scissor_was_enabled) {
+        SDL_Rect r;
+        r.x = (int)data->state.viewport.x;
+        r.y = (int)data->state.viewport.y;
+        r.w = (int)data->state.viewport.w;
+        r.h = (int)data->state.viewport.h;
+        SDL_SetGPUScissor(data->state.render_pass, &r);
+        data->state.scissor_was_enabled = false;
+    }
+}
+
+static void Draw(
+    GPU_RenderData *data, SDL_RenderCommand *cmd,
+    Uint32 num_verts,
+    Uint32 offset,
+    SDL_GPUPrimitiveType prim)
+{
+    if (!data->state.render_pass || data->state.color_attachment.load_op == SDL_GPU_LOADOP_CLEAR) {
+        RestartRenderPass(data);
+    }
+
+    GPU_VertexShaderID v_shader;
+    GPU_FragmentShaderID f_shader;
+    SDL_GPURenderPass *pass = data->state.render_pass;
+    GPU_TextureData *tdata = NULL;
+
+    if (cmd->data.draw.texture) {
+        tdata = (GPU_TextureData *)cmd->data.draw.texture->internal;
+    }
+
+    if (prim == SDL_GPU_PRIMITIVETYPE_TRIANGLELIST) {
+        if (cmd->data.draw.texture) {
+            v_shader = VERT_SHADER_TRI_TEXTURE;
+            f_shader = tdata->shader;
+        } else {
+            v_shader = VERT_SHADER_TRI_COLOR;
+            f_shader = FRAG_SHADER_COLOR;
+        }
+    } else {
+        v_shader = VERT_SHADER_LINEPOINT;
+        f_shader = FRAG_SHADER_COLOR;
+    }
+
+    GPU_PipelineParameters pipe_params;
+    SDL_zero(pipe_params);
+    pipe_params.blend_mode = cmd->data.draw.blend;
+    pipe_params.vert_shader = v_shader;
+    pipe_params.frag_shader = f_shader;
+    pipe_params.primitive_type = prim;
+
+    if (data->state.render_target) {
+        pipe_params.attachment_format = ((GPU_TextureData *)data->state.render_target->internal)->format;
+    } else {
+        pipe_params.attachment_format = data->backbuffer.format;
+    }
+
+    SDL_GPUGraphicsPipeline *pipe = GPU_GetPipeline(&data->pipeline_cache, &data->shaders, data->device, &pipe_params);
+
+    if (!pipe) {
+        return;
+    }
+
+    SetViewportAndScissor(data);
+    SDL_BindGPUGraphicsPipeline(data->state.render_pass, pipe);
+
+    if (tdata) {
+        SDL_GPUTextureSamplerBinding sampler_bind;
+        SDL_zero(sampler_bind);
+        sampler_bind.sampler = *SamplerPointer(data, cmd->data.draw.texture_address_mode, cmd->data.draw.texture->scaleMode);
+        sampler_bind.texture = tdata->texture;
+        SDL_BindGPUFragmentSamplers(pass, 0, &sampler_bind, 1);
+    }
+
+    SDL_GPUBufferBinding buffer_bind;
+    SDL_zero(buffer_bind);
+    buffer_bind.buffer = data->vertices.buffer;
+    buffer_bind.offset = offset;
+
+    SDL_BindGPUVertexBuffers(pass, 0, &buffer_bind, 1);
+    PushUniforms(data, cmd);
+    SDL_DrawGPUPrimitives(data->state.render_pass, num_verts, 1, 0, 0);
+}
+
+static void ReleaseVertexBuffer(GPU_RenderData *data)
+{
+    if (data->vertices.buffer) {
+        SDL_ReleaseGPUBuffer(data->device, data->vertices.buffer);
+    }
+
+    if (data->vertices.transfer_buf) {
+        SDL_ReleaseGPUTransferBuffer(data->device, data->vertices.transfer_buf);
+    }
+
+    data->vertices.buffer_size = 0;
+}
+
+static bool InitVertexBuffer(GPU_RenderData *data, Uint32 size)
+{
+    SDL_GPUBufferCreateInfo bci;
+    SDL_zero(bci);
+    bci.size = size;
+    bci.usage = SDL_GPU_BUFFERUSAGE_VERTEX;
+
+    data->vertices.buffer = SDL_CreateGPUBuffer(data->device, &bci);
+
+    if (!data->vertices.buffer) {
+        return false;
+    }
+
+    SDL_GPUTransferBufferCreateInfo tbci;
+    SDL_zero(tbci);
+    tbci.size = size;
+    tbci.usage = SDL_GPU_TRANSFERBUFFERUSAGE_UPLOAD;
+
+    data->vertices.transfer_buf = SDL_CreateGPUTransferBuffer(data->device, &tbci);
+
+    if (!data->vertices.transfer_buf) {
+        return false;
+    }
+
+    return true;
+}
+
+static bool UploadVertices(GPU_RenderData *data, void *vertices, size_t vertsize)
+{
+    if (vertsize == 0) {
+        return true;
+    }
+
+    if (vertsize > data->vertices.buffer_size) {
+        ReleaseVertexBuffer(data);
+        if (!InitVertexBuffer(data, (Uint32)vertsize)) {
+            return false;
+        }
+    }
+
+    void *staging_buf = SDL_MapGPUTransferBuffer(data->device, data->vertices.transfer_buf, true);
+    SDL_memcpy(staging_buf, vertices, vertsize);
+    SDL_UnmapGPUTransferBuffer(data->device, data->vertices.transfer_buf);
+
+    SDL_GPUCopyPass *pass = SDL_BeginGPUCopyPass(data->state.command_buffer);
+
+    if (!pass) {
+        return false;
+    }
+
+    SDL_GPUTransferBufferLocation src;
+    SDL_zero(src);
+    src.transfer_buffer = data->vertices.transfer_buf;
+
+    SDL_GPUBufferRegion dst;
+    SDL_zero(dst);
+    dst.buffer = data->vertices.buffer;
+    dst.size = (Uint32)vertsize;
+
+    SDL_UploadToGPUBuffer(pass, &src, &dst, true);
+    SDL_EndGPUCopyPass(pass);
+
+    return true;
+}
+
+// *** FIXME ***
+// We might be able to run these data uploads on a separate command buffer
+// which would allow us to avoid breaking render passes.
+// Honestly I'm a little skeptical of this entire approach,
+// we already have a command buffer structure
+// so it feels weird to be deferring the operations manually.
+// We could also fairly easily run the geometry transformations
+// on compute shaders instead of the CPU, which would be a HUGE performance win.
+// -cosmonaut
+static bool GPU_RunCommandQueue(SDL_Renderer *renderer, SDL_RenderCommand *cmd, void *vertices, size_t vertsize)
+{
+    GPU_RenderData *data = (GPU_RenderData *)renderer->internal;
+
+    if (!UploadVertices(data, vertices, vertsize)) {
+        return false;
+    }
+
+    data->state.color_attachment.load_op = SDL_GPU_LOADOP_LOAD;
+
+    if (renderer->target) {
+        GPU_TextureData *tdata = renderer->target->internal;
+        data->state.color_attachment.texture = tdata->texture;
+    } else {
+        data->state.color_attachment.texture = data->backbuffer.texture;
+    }
+
+    if (!data->state.color_attachment.texture) {
+        return SDL_SetError("Render target texture is NULL");
+    }
+
+    while (cmd) {
+        switch (cmd->command) {
+        case SDL_RENDERCMD_SETDRAWCOLOR:
+        {
+            data->state.draw_color = GetDrawCmdColor(renderer, cmd);
+            break;
+        }
+
+        case SDL_RENDERCMD_SETVIEWPORT:
+        {
+            SDL_Rect *viewport = &cmd->data.viewport.rect;
+            data->state.viewport.x = viewport->x;
+            data->state.viewport.y = viewport->y;
+            data->state.viewport.w = viewport->w;
+            data->state.viewport.h = viewport->h;
+            break;
+        }
+
+        case SDL_RENDERCMD_SETCLIPRECT:
+        {
+            const SDL_Rect *rect = &cmd->data.cliprect.rect;
+            data->state.scissor.x = (int)data->state.viewport.x + rect->x;
+            data->state.scissor.y = (int)data->state.viewport.y + rect->y;
+            data->state.scissor.w = rect->w;
+            data->state.scissor.h = rect->h;
+            data->state.scissor_enabled = cmd->data.cliprect.enabled;
+            break;
+        }
+
+        case SDL_RENDERCMD_CLEAR:
+        {
+            data->state.color_attachment.clear_color = GetDrawCmdColor(renderer, cmd);
+            data->state.color_attachment.load_op = SDL_GPU_LOADOP_CLEAR;
+            break;
+        }
+
+        case SDL_RENDERCMD_FILL_RECTS: // unused
+            break;
+
+        case SDL_RENDERCMD_COPY: // unused
+            break;
+
+        case SDL_RENDERCMD_COPY_EX: // unused
+            break;
+
+        case SDL_RENDERCMD_DRAW_LINES:
+        {
+            Uint32 count = (Uint32)cmd->data.draw.count;
+            Uint32 offset = (Uint32)cmd->data.draw.first;
+
+            if (count > 2) {
+                // joined lines cannot be grouped
+                Draw(data, cmd, count, offset, SDL_GPU_PRIMITIVETYPE_LINESTRIP);
+            } else {
+                // let's group non joined lines
+                SDL_RenderCommand *finalcmd = cmd;
+                SDL_RenderCommand *nextcmd = cmd->next;
+                SDL_BlendMode thisblend = cmd->data.draw.blend;
+
+                while (nextcmd) {
+                    const SDL_RenderCommandType nextcmdtype = nextcmd->command;
+                    if (nextcmdtype != SDL_RENDERCMD_DRAW_LINES) {
+                        break; // can't go any further on this draw call, different render command up next.
+                    } else if (nextcmd->data.draw.count != 2) {
+                        break; // can't go any further on this draw call, those are joined lines
+                    } else if (nextcmd->data.draw.blend != thisblend) {
+                        break; // can't go any further on this draw call, different blendmode copy up next.
+                    } else {
+                        finalcmd = nextcmd; // we can combine copy operations here. Mark this one as the furthest okay command.
+                        count += (Uint32)nextcmd->data.draw.count;
+                    }
+                    nextcmd = nextcmd->next;
+                }
+
+                Draw(data, cmd, count, offset, SDL_GPU_PRIMITIVETYPE_LINELIST);
+                cmd = finalcmd; // skip any copy commands we just combined in here.
+            }
+            break;
+        }
+
+        case SDL_RENDERCMD_DRAW_POINTS:
+        case SDL_RENDERCMD_GEOMETRY:
+        {
+            /* as long as we have the same copy command in a row, with the
+               same texture, we can combine them all into a single draw call. */
+            SDL_Texture *thistexture = cmd->data.draw.texture;
+            SDL_BlendMode thisblend = cmd->data.draw.blend;
+            const SDL_RenderCommandType thiscmdtype = cmd->command;
+            SDL_RenderCommand *finalcmd = cmd;
+            SDL_RenderCommand *nextcmd = cmd->next;
+            Uint32 count = (Uint32)cmd->data.draw.count;
+            Uint32 offset = (Uint32)cmd->data.draw.first;
+
+            while (nextcmd) {
+                const SDL_RenderCommandType nextcmdtype = nextcmd->command;
+                if (nextcmdtype != thiscmdtype) {
+                    break; // can't go any further on this draw call, different render command up next.
+                } else if (nextcmd->data.draw.texture != thistexture || nextcmd->data.draw.blend != thisblend) {
+                    // FIXME should we check address mode too?
+                    break; // can't go any further on this draw call, different texture/blendmode copy up next.
+                } else {
+                    finalcmd = nextcmd; // we can combine copy operations here. Mark this one as the furthest okay command.
+                    count += (Uint32)nextcmd->data.draw.count;
+                }
+                nextcmd = nextcmd->next;
+            }
+
+            SDL_GPUPrimitiveType prim = SDL_GPU_PRIMITIVETYPE_TRIANGLELIST; // SDL_RENDERCMD_GEOMETRY
+            if (thiscmdtype == SDL_RENDERCMD_DRAW_POINTS) {
+                prim = SDL_GPU_PRIMITIVETYPE_POINTLIST;
+            }
+
+            Draw(data, cmd, count, offset, prim);
+
+            cmd = finalcmd; // skip any copy commands we just combined in here.
+            break;
+        }
+
+        case SDL_RENDERCMD_NO_OP:
+            break;
+        }
+
+        cmd = cmd->next;
+    }
+
+    if (data->state.color_attachment.load_op == SDL_GPU_LOADOP_CLEAR) {
+        RestartRenderPass(data);
+    }
+
+    if (data->state.render_pass) {
+        SDL_EndGPURenderPass(data->state.render_pass);
+        data->state.render_pass = NULL;
+    }
+
+    return true;
+}
+
+static SDL_Surface *GPU_RenderReadPixels(SDL_Renderer *renderer, const SDL_Rect *rect)
+{
+    GPU_RenderData *data = (GPU_RenderData *)renderer->internal;
+    SDL_GPUTexture *gpu_tex;
+    SDL_PixelFormat pixfmt;
+
+    if (data->state.render_target) {
+        SDL_Texture *texture = data->state.render_target;
+        GPU_TextureData *texdata = texture->internal;
+        gpu_tex = texdata->texture;
+        pixfmt = texture->format;
+    } else {
+        gpu_tex = data->backbuffer.texture;
+        pixfmt = TexFormatToPixFormat(data->backbuffer.format);
+
+        if (pixfmt == SDL_PIXELFORMAT_UNKNOWN) {
+            SDL_SetError("Unsupported backbuffer format");
+            return NULL;
+        }
+    }
+
+    Uint32 bpp = SDL_BYTESPERPIXEL(pixfmt);
+    size_t row_size, image_size;
+
+    if (!SDL_size_mul_check_overflow(rect->w, bpp, &row_size) ||
+        !SDL_size_mul_check_overflow(rect->h, row_size, &image_size)) {
+        SDL_SetError("read size overflow");
+        return NULL;
+    }
+
+    SDL_Surface *surface = SDL_CreateSurface(rect->w, rect->h, pixfmt);
+
+    if (!surface) {
+        return NULL;
+    }
+
+    SDL_GPUTransferBufferCreateInfo tbci;
+    SDL_zero(tbci);
+    tbci.size = (Uint32)image_size;
+    tbci.usage = SDL_GPU_TRANSFERBUFFERUSAGE_DOWNLOAD;
+
+    SDL_GPUTransferBuffer *tbuf = SDL_CreateGPUTransferBuffer(data->device, &tbci);
+
+    if (!tbuf) {
+        return NULL;
+    }
+
+    SDL_GPUCopyPass *pass = SDL_BeginGPUCopyPass(data->state.command_buffer);
+
+    SDL_GPUTextureRegion src;
+    SDL_zero(src);
+    src.texture = gpu_tex;
+    src.x = rect->x;
+    src.y = rect->y;
+    src.w = rect->w;
+    src.h = rect->h;
+    src.d = 1;
+
+    SDL_GPUTextureTransferInfo dst;
+    SDL_zero(dst);
+    dst.transfer_buffer = tbuf;
+    dst.rows_per_layer = rect->h;
+    dst.pixels_per_row = rect->w;
+
+    SDL_DownloadFromGPUTexture(pass, &src, &dst);
+    SDL_EndGPUCopyPass(pass);
+
+    SDL_GPUFence *fence = SDL_SubmitGPUCommandBufferAndAcquireFence(data->state.command_buffer);
+    SDL_WaitForGPUFences(data->device, true, &fence, 1);
+    SDL_ReleaseGPUFence(data->device, fence);
+    data->state.command_buffer = SDL_AcquireGPUCommandBuffer(data->device);
+
+    void *mapped_tbuf = SDL_MapGPUTransferBuffer(data->device, tbuf, false);
+
+    if ((size_t)surface->pitch == row_size) {
+        SDL_memcpy(surface->pixels, mapped_tbuf, image_size);
+    } else {
+        Uint8 *input = mapped_tbuf;
+        Uint8 *output = surface->pixels;
+
+        for (int row = 0; row < rect->h; ++row) {
+            SDL_memcpy(output, input, row_size);
+            output += surface->pitch;
+            input += row_size;
+        }
+    }
+
+    SDL_UnmapGPUTransferBuffer(data->device, tbuf);
+    SDL_ReleaseGPUTransferBuffer(data->device, tbuf);
+
+    return surface;
+}
+
+static bool CreateBackbuffer(GPU_RenderData *data, Uint32 w, Uint32 h, SDL_GPUTextureFormat fmt)
+{
+    SDL_GPUTextureCreateInfo tci;
+    SDL_zero(tci);
+    tci.width = w;
+    tci.height = h;
+    tci.format = fmt;
+    tci.layer_count_or_depth = 1;
+    tci.num_levels = 1;
+    tci.sample_count = SDL_GPU_SAMPLECOUNT_1;
+    tci.usage = SDL_GPU_TEXTUREUSAGE_COLOR_TARGET | SDL_GPU_TEXTUREUSAGE_SAMPLER;
+
+    data->backbuffer.texture = SDL_CreateGPUTexture(data->device, &tci);
+    data->backbuffer.width = w;
+    data->backbuffer.height = h;
+    data->backbuffer.format = fmt;
+
+    if (!data->backbuffer.texture) {
+        return false;
+    }
+
+    return true;
+}
+
+static bool GPU_RenderPresent(SDL_Renderer *renderer)
+{
+    GPU_RenderData *data = (GPU_RenderData *)renderer->internal;
+
+    SDL_GPUTexture *swapchain;
+    Uint32 swapchain_texture_width, swapchain_texture_height;
+    bool result = SDL_WaitAndAcquireGPUSwapchainTexture(data->state.command_buffer, renderer->window, &swapchain, &swapchain_texture_width, &swapchain_texture_height);
+
+    if (!result) {
+        SDL_LogError(SDL_LOG_CATEGORY_RENDER, "Failed to acquire swapchain texture: %s", SDL_GetError());
+    }
+
+    if (swapchain != NULL) {
+        SDL_GPUBlitInfo blit_info;
+        SDL_zero(blit_info);
+
+        blit_info.source.texture = data->backbuffer.texture;
+        blit_info.source.w = data->backbuffer.width;
+        blit_info.source.h = data->backbuffer.height;
+        blit_info.destination.texture = swapchain;
+        blit_info.destination.w = swapchain_texture_width;
+        blit_info.destination.h = swapchain_texture_height;
+        blit_info.load_op = SDL_GPU_LOADOP_DONT_CARE;
+        blit_info.filter = SDL_GPU_FILTER_LINEAR;
+
+        SDL_BlitGPUTexture(data->state.command_buffer, &blit_info);
+
+        SDL_SubmitGPUCommandBuffer(data->state.command_buffer);
+
+        if (swapchain_texture_width != data->backbuffer.width || swapchain_texture_height != data->backbuffer.height) {
+            SDL_ReleaseGPUTexture(data->device, data->backbuffer.texture);
+            CreateBackbuffer(data, swapchain_texture_width, swapchain_texture_height, SDL_GetGPUSwapchainTextureFormat(data->device, renderer->window));
+        }
+    } else {
+        SDL_SubmitGPUCommandBuffer(data->state.command_buffer);
+    }
+
+    data->state.command_buffer = SDL_AcquireGPUCommandBuffer(data->device);
+
+    return true;
+}
+
+static void GPU_DestroyTexture(SDL_Renderer *renderer, SDL_Texture *texture)
+{
+    GPU_RenderData *renderdata = (GPU_RenderData *)renderer->internal;
+    GPU_TextureData *data = (GPU_TextureData *)texture->internal;
+
+    if (renderdata->state.render_target == texture) {
+        renderdata->state.render_target = NULL;
+    }
+
+    if (!data) {
+        return;
+    }
+
+    SDL_ReleaseGPUTexture(renderdata->device, data->texture);
+    SDL_free(data->pixels);
+    SDL_free(data);
+    texture->internal = NULL;
+}
+
+static void GPU_DestroyRenderer(SDL_Renderer *renderer)
+{
+    GPU_RenderData *data = (GPU_RenderData *)renderer->internal;
+
+    if (!data) {
+        return;
+    }
+
+    if (data->state.command_buffer) {
+        SDL_SubmitGPUCommandBuffer(data->state.command_buffer);
+        data->state.command_buffer = NULL;
+    }
+
+    for (Uint32 i = 0; i < sizeof(data->samplers) / sizeof(SDL_GPUSampler *); ++i) {
+        SDL_ReleaseGPUSampler(data->device, ((SDL_GPUSampler **)data->samplers)[i]);
+    }
+
+    if (data->backbuffer.texture) {
+        SDL_ReleaseGPUTexture(data->device, data->backbuffer.texture);
+    }
+
+    if (renderer->window) {
+        SDL_ReleaseWindowFromGPUDevice(data->device, renderer->window);
+    }
+
+    ReleaseVertexBuffer(data);
+    GPU_DestroyPipelineCache(&data->pipeline_cache);
+    GPU_ReleaseShaders(&data->shaders, data->device);
+    SDL_DestroyGPUDevice(data->device);
+
+    SDL_free(data);
+}
+
+static bool ChoosePresentMode(SDL_GPUDevice *device, SDL_Window *window, const int vsync, SDL_GPUPresentMode *out_mode)
+{
+    SDL_GPUPresentMode mode;
+
+    switch (vsync) {
+    case 0:
+        mode = SDL_GPU_PRESENTMODE_MAILBOX;
+
+        if (!SDL_WindowSupportsGPUPresentMode(device, window, mode)) {
+            mode = SDL_GPU_PRESENTMODE_IMMEDIATE;
+
+            if (!SDL_WindowSupportsGPUPresentMode(device, window, mode)) {
+                mode = SDL_GPU_PRESENTMODE_VSYNC;
+            }
+        }
+
+        // FIXME should we return an error if both mailbox and immediate fail?
+        break;
+
+    case 1:
+        mode = SDL_GPU_PRESENTMODE_VSYNC;
+        break;
+
+    default:
+        return SDL_Unsupported();
+    }
+
+    *out_mode = mode;
+    return true;
+}
+
+static bool GPU_SetVSync(SDL_Renderer *renderer, const int vsync)
+{
+    GPU_RenderData *data = (GPU_RenderData *)renderer->internal;
+    SDL_GPUPresentMode mode = SDL_GPU_PRESENTMODE_VSYNC;
+
+    if (!ChoosePresentMode(data->device, renderer->window, vsync, &mode)) {
+        return false;
+    }
+
+    if (mode != data->swapchain.present_mode) {
+        // XXX returns bool instead of SDL-style error code
+        if (SDL_SetGPUSwapchainParameters(data->device, renderer->window, data->swapchain.composition, mode)) {
+            data->swapchain.present_mode = mode;
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+static bool InitSamplers(GPU_RenderData *data)
+{
+    struct
+    {
+        struct
+        {
+            SDL_TextureAddressMode address_mode;
+            SDL_ScaleMode scale_mode;
+        } sdl;
+        struct
+        {
+            SDL_GPUSamplerAddressMode address_mode;
+            SDL_GPUFilter filter;
+            SDL_GPUSamplerMipmapMode mipmap_mode;
+            Uint32 anisotropy;
+        } gpu;
+    } configs[] = {
+        {
+            { SDL_TEXTURE_ADDRESS_CLAMP, SDL_SCALEMODE_NEAREST },
+            { SDL_GPU_SAMPLERADDRESSMODE_REPEAT, SDL_GPU_FILTER_NEAREST, SDL_GPU_SAMPLERMIPMAPMODE_NEAREST, 0 },
+        },
+        {
+            { SDL_TEXTURE_ADDRESS_CLAMP, SDL_SCALEMODE_LINEAR },
+            { SDL_GPU_SAMPLERADDRESSMODE_REPEAT, SDL_GPU_FILTER_LINEAR, SDL_GPU_SAMPLERMIPMAPMODE_LINEAR, 0 },
+        },
+        {
+            { SDL_TEXTURE_ADDRESS_WRAP, SDL_SCALEMODE_NEAREST },
+            { SDL_GPU_SAMPLERADDRESSMODE_REPEAT, SDL_GPU_FILTER_NEAREST, SDL_GPU_SAMPLERMIPMAPMODE_NEAREST, 0 },
+        },
+        {
+            { SDL_TEXTURE_ADDRESS_WRAP, SDL_SCALEMODE_LINEAR },
+            { SDL_GPU_SAMPLERADDRESSMODE_REPEAT, SDL_GPU_FILTER_LINEAR, SDL_GPU_SAMPLERMIPMAPMODE_LINEAR, 0 },
+        },
+    };
+
+    for (Uint32 i = 0; i < SDL_arraysize(configs); ++i) {
+        SDL_GPUSamplerCreateInfo sci;
+        SDL_zero(sci);
+        sci.max_anisotropy = configs[i].gpu.anisotropy;
+        sci.enable_anisotropy = configs[i].gpu.anisotropy > 0;
+        sci.address_mode_u = sci.address_mode_v = sci.address_mode_w = configs[i].gpu.address_mode;
+        sci.min_filter = sci.mag_filter = configs[i].gpu.filter;
+        sci.mipmap_mode = configs[i].gpu.mipmap_mode;
+
+        SDL_GPUSampler *sampler = SDL_CreateGPUSampler(data->device, &sci);
+
+        if (sampler == NULL) {
+            return false;
+        }
+
+        *SamplerPointer(data, configs[i].sdl.address_mode, configs[i].sdl.scale_mode) = sampler;
+    }
+
+    return true;
+}
+
+static bool GPU_CreateRenderer(SDL_Renderer *renderer, SDL_Window *window, SDL_PropertiesID create_props)
+{
+    GPU_RenderData *data = NULL;
+
+    SDL_SetupRendererColorspace(renderer, create_props);
+
+    if (renderer->output_colorspace != SDL_COLORSPACE_SRGB) {
+        // TODO
+        return SDL_SetError("Unsupported output colorspace");
+    }
+
+    data = (GPU_RenderData *)SDL_calloc(1, sizeof(*data));
+    if (!data) {
+        return false;
+    }
+
+    renderer->SupportsBlendMode = GPU_SupportsBlendMode;
+    renderer->CreateTexture = GPU_CreateTexture;
+    renderer->UpdateTexture = GPU_UpdateTexture;
+    renderer->LockTexture = GPU_LockTexture;
+    renderer->UnlockTexture = GPU_UnlockTexture;
+    renderer->SetTextureScaleMode = GPU_SetTextureScaleMode;
+    renderer->SetRenderTarget = GPU_SetRenderTarget;
+    renderer->QueueSetViewport = GPU_QueueNoOp;
+    renderer->QueueSetDrawColor = GPU_QueueNoOp;
+    renderer->QueueDrawPoints = GPU_QueueDrawPoints;
+    renderer->QueueDrawLines = GPU_QueueDrawPoints; // lines and points queue vertices the same way.
+    renderer->QueueGeometry = GPU_QueueGeometry;
+    renderer->InvalidateCachedState = GPU_InvalidateCachedState;
+    renderer->RunCommandQueue = GPU_RunCommandQueue;
+    renderer->RenderReadPixels = GPU_RenderReadPixels;
+    renderer->RenderPresent = GPU_RenderPresent;
+    renderer->DestroyTexture = GPU_DestroyTexture;
+    renderer->DestroyRenderer = GPU_DestroyRenderer;
+    renderer->SetVSync = GPU_SetVSync;
+    renderer->internal = data;
+    renderer->window = window;
+    renderer->name = GPU_RenderDriver.name;
+
+    bool debug = SDL_GetBooleanProperty(create_props, SDL_PROP_GPU_DEVICE_CREATE_DEBUGMODE_BOOLEAN, false);
+    bool lowpower = SDL_GetBooleanProperty(create_props, SDL_PROP_GPU_DEVICE_CREATE_PREFERLOWPOWER_BOOLEAN, false);
+
+    // Prefer environment variables/hints if they exist, otherwise defer to properties
+    debug = SDL_GetHintBoolean(SDL_HINT_RENDER_GPU_DEBUG, debug);
+    lowpower = SDL_GetHintBoolean(SDL_HINT_RENDER_GPU_LOW_POWER, lowpower);
+
+    SDL_SetBooleanProperty(create_props, SDL_PROP_GPU_DEVICE_CREATE_DEBUGMODE_BOOLEAN, debug);
+    SDL_SetBooleanProperty(create_props, SDL_PROP_GPU_DEVICE_CREATE_PREFERLOWPOWER_BOOLEAN, lowpower);
+
+    GPU_FillSupportedShaderFormats(create_props);
+    data->device = SDL_CreateGPUDeviceWithProperties(create_props);
+
+    if (!data->device) {
+        return false;
+    }
+
+    if (!GPU_InitShaders(&data->shaders, data->device)) {
+        return false;
+    }
+
+    if (!GPU_InitPipelineCache(&data->pipeline_cache, data->device)) {
+        return false;
+    }
+
+    // XXX what's a good initial size?
+    if (!InitVertexBuffer(data, 1 << 16)) {
+        return false;
+    }
+
+    if (!InitSamplers(data)) {
+        return false;
+    }
+
+    if (!SDL_ClaimWindowForGPUDevice(data->device, window)) {
+        return false;
+    }
+
+    data->swapchain.composition = SDL_GPU_SWAPCHAINCOMPOSITION_SDR;
+    data->swapchain.present_mode = SDL_GPU_PRESENTMODE_VSYNC;
+
+    int vsync = (int)SDL_GetNumberProperty(create_props, SDL_PROP_RENDERER_CREATE_PRESENT_VSYNC_NUMBER, 0);
+    ChoosePresentMode(data->device, window, vsync, &data->swapchain.present_mode);
+
+    SDL_SetGPUSwapchainParameters(data->device, window, data->swapchain.composition, data->swapchain.present_mode);
+
+    SDL_SetGPUAllowedFramesInFlight(data->device, 1);
+
+    SDL_AddSupportedTextureFormat(renderer, SDL_PIXELFORMAT_BGRA32);
+    SDL_AddSupportedTextureFormat(renderer, SDL_PIXELFORMAT_RGBA32);
+    SDL_AddSupportedTextureFormat(renderer, SDL_PIXELFORMAT_BGRX32);
+    SDL_AddSupportedTextureFormat(renderer, SDL_PIXELFORMAT_RGBX32);
+
+    SDL_SetNumberProperty(SDL_GetRendererProperties(renderer), SDL_PROP_RENDERER_MAX_TEXTURE_SIZE_NUMBER, 16384);
+
+    data->state.draw_color.r = 1.0f;
+    data->state.draw_color.g = 1.0f;
+    data->state.draw_color.b = 1.0f;
+    data->state.draw_color.a = 1.0f;
+    data->state.viewport.min_depth = 0;
+    data->state.viewport.max_depth = 1;
+    data->state.command_buffer = SDL_AcquireGPUCommandBuffer(data->device);
+
+    int w, h;
+    SDL_GetWindowSizeInPixels(window, &w, &h);
+
+    if (!CreateBackbuffer(data, w, h, SDL_GetGPUSwapchainTextureFormat(data->device, window))) {
+        return false;
+    }
+
+    SDL_SetPointerProperty(SDL_GetRendererProperties(renderer), SDL_PROP_RENDERER_GPU_DEVICE_POINTER, data->device);
+
+    return true;
+}
+
+SDL_RenderDriver GPU_RenderDriver = {
+    GPU_CreateRenderer, "gpu"
+};
+
+#endif // SDL_VIDEO_RENDER_GPU