1 files changed, 151 insertions, 0 deletions

diff --git a/gfx/src/core/framebuffer.c b/gfx/src/core/framebuffer.c
new file mode 100644
index 0000000..76d9002
--- /dev/null
+++ b/gfx/src/core/framebuffer.c
@@ -0,0 +1,151 @@
+#include "framebuffer.h"
+
+#include "renderbuffer.h"
+#include "texture.h"
+
+#include <gfx_assert.h>
+
+#include <error.h>
+
+static void framebuffer_attach_colour(
+    FrameBuffer* framebuffer, const FrameBufferAttachment* attachment) {
+  assert(framebuffer);
+  assert(attachment);
+
+  switch (attachment->type) {
+  case FrameBufferNoAttachment:
+    break;
+  case FrameBufferTexture:
+    glFramebufferTexture2D(
+        GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
+        attachment->texture.texture->id, attachment->texture.mip_level);
+    break;
+  case FrameBufferCubemapTexture:
+    glFramebufferTexture2D(
+        GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
+        to_GL_cubemap_face(attachment->cubemap.face),
+        attachment->cubemap.texture->id, attachment->cubemap.mip_level);
+    break;
+  case FrameBufferRenderBuffer:
+    glFramebufferRenderbuffer(
+        GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER,
+        attachment->renderbuffer->id);
+    break;
+  }
+
+  ASSERT_GL;
+}
+
+static void framebuffer_attach_depth(
+    FrameBuffer* framebuffer, const FrameBufferAttachment* attachment) {
+  assert(framebuffer);
+  assert(attachment);
+
+  switch (attachment->type) {
+  case FrameBufferNoAttachment:
+    break;
+  case FrameBufferTexture:
+    glFramebufferTexture2D(
+        GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_DEPTH_COMPONENT,
+        attachment->texture.texture->id, attachment->texture.mip_level);
+    break;
+  // TODO: Could distinguish between colour and depth attachment types to make
+  // this a compile-time error.
+  case FrameBufferCubemapTexture:
+    log_error("Cannot use a cubemap texture as a depth framebuffer attachment");
+    break;
+  case FrameBufferRenderBuffer:
+    glFramebufferRenderbuffer(
+        GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER,
+        attachment->renderbuffer->id);
+    break;
+  }
+
+  ASSERT_GL;
+}
+
+bool gfx_init_framebuffer(
+    FrameBuffer* framebuffer, const FrameBufferDesc* desc) {
+  assert(framebuffer);
+  assert(desc);
+
+  glGenFramebuffers(1, &framebuffer->id);
+  if (!framebuffer->id) {
+    log_error("glGenFramebuffers() failed");
+    return false;
+  }
+
+  // Allow incomplete framebuffers for flexibility.
+  // Attach buffers and check the framebuffer status only if buffers are given
+  // up front.
+  if (desc->colour.type != FrameBufferNoAttachment ||
+      desc->depth.type != FrameBufferNoAttachment) {
+    // TODO: Could use the "named" API to avoid having to bind the framebuffer.
+    glBindFramebuffer(GL_FRAMEBUFFER, framebuffer->id);
+    framebuffer_attach_colour(framebuffer, &desc->colour);
+    framebuffer_attach_depth(framebuffer, &desc->depth);
+    if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
+      log_error("glCheckFramebufferStatus() failed");
+      gfx_del_framebuffer(framebuffer);
+      return false;
+    }
+    glBindFramebuffer(GL_FRAMEBUFFER, 0);
+  }
+
+  ASSERT_GL;
+  return true;
+}
+
+bool gfx_framebuffer_attach_colour(
+    FrameBuffer* framebuffer, const FrameBufferAttachment* attachment) {
+  assert(framebuffer);
+  assert(attachment);
+
+  // TODO: Could use the "named" API to avoid having to bind the framebuffer.
+  glBindFramebuffer(GL_FRAMEBUFFER, framebuffer->id);
+  framebuffer_attach_colour(framebuffer, attachment);
+  if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
+    log_error("glCheckFramebufferStatus() failed");
+    return false;
+  }
+  return true;
+}
+
+bool gfx_framebuffer_attach_depth(
+    FrameBuffer* framebuffer, const FrameBufferAttachment* attachment) {
+  assert(framebuffer);
+  assert(attachment);
+
+  // TODO: Could use the "named" API to avoid having to bind the framebuffer.
+  glBindFramebuffer(GL_FRAMEBUFFER, framebuffer->id);
+  framebuffer_attach_depth(framebuffer, attachment);
+  if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
+    log_error("glCheckFramebufferStatus() failed");
+    return false;
+  }
+  return true;
+}
+
+void gfx_del_framebuffer(FrameBuffer* framebuffer) {
+  assert(framebuffer);
+  if (framebuffer->id) {
+    glDeleteFramebuffers(1, &framebuffer->id);
+    framebuffer->id = 0;
+  }
+}
+
+void gfx_activate_framebuffer(const FrameBuffer* framebuffer) {
+  assert(framebuffer);
+  glBindFramebuffer(GL_FRAMEBUFFER, framebuffer->id);
+}
+
+void gfx_deactivate_framebuffer(const FrameBuffer* framebuffer) {
+  assert(framebuffer);
+  glBindFramebuffer(GL_FRAMEBUFFER, 0);
+}
+
+void gfx_framebuffer_set_viewport(
+    FrameBuffer* framebuffer, int x, int y, int width, int height) {
+  assert(framebuffer);
+  glViewport(x, y, width, height);
+}