From e0dd69febc8f73b0e39e14d070ecf6b73bbe2d4f Mon Sep 17 00:00:00 2001
From: 3gg <3gg@shellblade.net>
Date: Sat, 14 Feb 2026 19:06:49 -0800
Subject: Use float colour. First step towards directional lighting

---
 include/swgfx.h | 29 ++++++++++++++++-------------
 1 file changed, 16 insertions(+), 13 deletions(-)

(limited to 'include')

diff --git a/include/swgfx.h b/include/swgfx.h
index 452847c..d527f02 100644
--- a/include/swgfx.h
+++ b/include/swgfx.h
@@ -30,8 +30,8 @@ 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 struct sgVec3 { union { struct { R r, g, b; };    struct { R x, y, z; };    }; } sgVec3;
+typedef struct sgVec4 { union { struct { R r, g, b, a; }; struct { R x, y, z, w; }; }; } sgVec4;
 
 typedef sgVec3 sgNormal;
 
@@ -50,14 +50,17 @@ typedef uint16_t sgIdx;
 typedef struct   sgVertIdx { sgIdx pos, uv, normal; } sgVertIdx;
 typedef struct   sgTriIdx  { sgVertIdx v0, v1, v2;  } sgTriIdx;
 
-typedef struct sgBgra { uint8_t b, g, r, a; } sgBgra;
-typedef struct sgRgba { uint8_t r, g, b, a; } sgRgba;
-// TODO: Should we use real-valued colours?
+typedef struct sgRgba   { uint8_t r, g, b, a; } sgRgba;
+typedef struct sgBgra   { uint8_t b, g, r, a; } sgBgra;
+
+typedef sgVec3 sgColour3;
+typedef sgVec4 sgColour4;
 typedef sgRgba sgPixel;
 // TODO: Expose a macro to control the desired surface format.
 typedef sgBgra sgScreenPixel;
 
 typedef uint16_t sgTextureId;
+typedef sgRgba   sgTexel;
 
 typedef enum sgTextureFilter {
   sgNearest,
@@ -67,7 +70,7 @@ typedef enum sgTextureFilter {
 typedef struct sgImage {
   int      width;
   int      height;
-  sgPixel* pixels;
+  sgTexel* pixels;
 } sgImage;
 
 typedef struct swgfx swgfx;
@@ -87,8 +90,8 @@ void   sgDel(swgfx**);
 
 // TODO: Write client app first, then implement the functions below in the C file.
 
-sgPixel* sgColourBuffer(swgfx*);
-void     sgPresent(swgfx*, sgVec2i dimensions, sgScreenPixel* screen);
+sgColour4* sgColourBuffer(swgfx*);
+void       sgPresent(swgfx*, sgVec2i dimensions, sgScreenPixel* screen);
 
 void sgModelId    (swgfx*);
 void sgModel      (swgfx*, sgVec3 position, sgVec3 right, sgVec3 up, sgVec3 forward);
@@ -101,7 +104,7 @@ void sgTextureRegister(swgfx*, sgTextureId, const sgImage*, sgTextureFilter);
 void sgTextureActivate(swgfx*, sgTextureId);
 
 void sgClear(swgfx*);
-void sgPixels(swgfx*, size_t count, const sgVec2i* positions, sgPixel colour);
+void sgPixels(swgfx*, size_t count, const sgVec2i* positions, sgColour4);
 void sgQuads (swgfx*, size_t count, const sgQuad*);
 void sgQuadsi(swgfx*, size_t count, const sgQuadi*);
 void sgTriangles2    (swgfx*, size_t count, const sgTri2*);
@@ -112,13 +115,13 @@ void sgTrianglesIndexed(swgfx*, size_t numIndices, const sgIdx* indices, const s
 void sgTrianglesIndexedNonUniform(swgfx*, size_t numTris, const sgTriIdx* tris, const sgVec3* positions, const sgVec2* texcoords, const sgVec3* normals);
 
 void sgLighting(swgfx*);
-void sgAmbient(swgfx*, sgVec3 ambient);
-// TODO: Implement directional lights.
+void sgAmbient    (swgfx*, sgColour3);
+void sgDirectional(swgfx*, sgColour3, sgVec3 direction);
 
 void sgDepth(swgfx*);
 void sgNormals(swgfx*);
 
-void sgGamma   (swgfx*, sgPixel*, int width, int height);
-void sgGammaInv(swgfx*, sgPixel*, int width, int height);
+void sgGamma   (swgfx*, sgTexel*,   int width, int height);
+void sgGammaInv(swgfx*, sgColour4*, int width, int height);
 
 sgCounters sgGetCounters(const swgfx*);
-- 
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