From 403730174aeaadcf7a8aad842bc5319050411ef9 Mon Sep 17 00:00:00 2001
From: 3gg <3gg@shellblade.net>
Date: Sun, 16 Nov 2025 18:23:37 -0800
Subject: Initial commit

---
 include/swgfx.h | 68 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)
 create mode 100644 include/swgfx.h

(limited to 'include')

diff --git a/include/swgfx.h b/include/swgfx.h
new file mode 100644
index 0000000..b6dc769
--- /dev/null
+++ b/include/swgfx.h
@@ -0,0 +1,68 @@
+/*
+Software rendering library.
+
+Cooridnate systems:
+- Pixel coordinates (i,j) refer to the center of the pixel.
+  Thus, real-valued coordinates (x,y) with no fractional part point at the pixel center.
+- Viewport origin is the top-left corner of the screen.
+  The viewport axes extend down and to the right.
+
+Multi-threading:
+- Internal resources (swgfx context) are externally synchronized.
+- External resources (colour buffer) are internally synchronized.
+*/
+#pragma once
+
+#include <stddef.h>
+#include <stdint.h>
+
+typedef float R;
+
+typedef struct sgVec2i { int x, y; }       sgVec2i;
+typedef struct sgVec2  { R   x, y; }       sgVec2;
+typedef struct sgVec3  { R   x, y, z; }    sgVec3;
+typedef struct sgVec4  { R   x, y, z, w; } sgVec4;
+
+typedef sgVec3 sgNormal;
+
+typedef struct sgQuadi { sgVec2i p0, p1; }     sgQuadi;
+typedef struct sgQuad  { sgVec2  p0, p1; }     sgQuad;
+typedef struct sgTri2  { sgVec2  p0, p1, p2; } sgTri2;
+typedef struct sgTri3  { sgVec3  p0, p1, p2; } sgTri3;
+
+// TODO: Should we use real-valued colours?
+typedef struct sgPixel { uint8_t r, g, b, a; } sgPixel;
+
+typedef struct swgfx swgfx;
+
+swgfx* sgNew();
+void   sgDel(swgfx**);
+
+// TODO: Write client app first, then implement the functions below in the C file.
+
+void sgColourBuffer(swgfx*, sgVec2i dimensions, sgPixel* buffer);
+void sgPresent     (swgfx*, sgVec2i dimensions, sgPixel* screen);
+
+void sgCam        (swgfx*, sgVec3 position, sgVec3 forward);
+void sgOrtho      (swgfx*, R left, R right, R top, R bottom, R near, R far);
+void sgPerspective(swgfx*, R fovy, R aspect, R near, R far);
+void sgViewport   (swgfx*, int x0, int y0, int width, int height);
+
+void sgClear(swgfx*);
+void sgPixels(swgfx*, size_t count, const sgVec2i* positions, sgPixel colour);
+void sgQuads (swgfx*, size_t count, const sgQuad*);
+void sgQuadsi(swgfx*, size_t count, const sgQuadi*);
+void sgTriangles2    (swgfx*, size_t count, const sgTri2*);
+void sgTriangleStrip2(swgfx*, size_t count, const sgVec2*);
+void sgTriangles     (swgfx*, size_t count, const sgTri3*, const sgNormal*);
+void sgTriangleStrip (swgfx*, size_t count, const sgVec3*, const sgNormal*);
+
+void sgCheck(swgfx*);
+
+// Memory
+#define SG_ALIGN 64
+#define SG_ALIGN_PTR(P) ((uintptr_t)(P) & (~(SG_ALIGN-1)))
+#define SG_ALIGN_ALLOC(COUNT, TYPE) (TYPE*)sgAlloc(1, COUNT * sizeof(TYPE))
+#define SG_FREE(PP) sgFree((void**)PP)
+void* sgAlloc(size_t count, size_t size);
+void  sgFree(void**);
-- 
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