Actually implement fixed vertex attribute support

examples/simple_tri/source/main.c

@@ -43,6 +43,10 @@ static void sceneInit(void)
 	C3D_AttrInfo* attrInfo = C3D_GetAttrInfo();
 	AttrInfo_Init(attrInfo);
 	AttrInfo_AddLoader(attrInfo, 0, GPU_FLOAT, 3); // v0=position
+	AttrInfo_AddFixed(attrInfo, 1); // v1=color
+
+	// Set the fixed attribute (color) to solid white
+	C3D_FixedAttribSet(1, 1.0, 1.0, 1.0, 1.0);
 
 	// Compute the projection matrix
 	Mtx_OrthoTilt(&projection, 0.0, 400.0, 0.0, 240.0, 0.0, 1.0);

examples/simple_tri/source/vshader.v.pica

@@ -15,6 +15,7 @@
 
 ; Inputs (defined as aliases for convenience)
 .alias inpos v0
+.alias inclr v1
 
 .bool test
 
@@ -29,8 +30,8 @@
 	dp4 outpos.z, projection[2], r0
 	dp4 outpos.w, projection[3], r0
 
-	; outclr = solid white color
+	; outclr = inclr
-	mov outclr, ones
+	mov outclr, inclr
 
 	; We're finished
 	end

include/c3d/base.h

@@ -36,3 +36,15 @@ static inline void C3D_Flush(void)
 	C3D_FlushAsync();
 	C3D_FlushAwait();
 }
+
+// Fixed vertex attributes
+C3D_FVec* C3D_FixedAttribGetWritePtr(int id);
+
+static inline void C3D_FixedAttribSet(int id, float x, float y, float z, float w)
+{
+	C3D_FVec* ptr = C3D_FixedAttribGetWritePtr(id);
+	ptr->x = x;
+	ptr->y = y;
+	ptr->z = z;
+	ptr->w = w;
+}

source/base.c

@@ -55,6 +55,8 @@ static void C3Di_AptEventHook(APT_HookType hookType, void* param)
 			C3Di_DirtyUniforms(GPU_VERTEX_SHADER);
 			C3Di_DirtyUniforms(GPU_GEOMETRY_SHADER);
 
+			ctx->fixedAttribDirty |= ctx->fixedAttribEverDirty;
+
 			C3D_LightEnv* env = ctx->lightEnv;
 			if (env)
 				env->Dirty(env);
@@ -98,6 +100,9 @@ bool C3D_Init(size_t cmdBufSize)
 	for (i = 0; i < 6; i ++)
 		TexEnv_Init(&ctx->texEnv[i]);
 
+	ctx->fixedAttribDirty = 0;
+	ctx->fixedAttribEverDirty = 0;
+
 	aptHook(&hookCookie, C3Di_AptEventHook, NULL);
 
 	return true;
@@ -230,6 +235,19 @@ void C3Di_UpdateContext(void)
 	if (env)
 		env->Update(env);
 
+	if (ctx->fixedAttribDirty)
+	{
+		for (i = 0; i < 12; i ++)
+		{
+			if (!(ctx->fixedAttribDirty & BIT(i))) continue;
+			C3D_FVec* v = &ctx->fixedAttribs[i];
+
+			GPUCMD_AddWrite(GPUREG_FIXEDATTRIB_INDEX, i);
+			C3D_ImmSendAttrib(v->x, v->y, v->z, v->w);
+		}
+		ctx->fixedAttribDirty = 0;
+	}
+
 	C3D_UpdateUniforms(GPU_VERTEX_SHADER);
 	C3D_UpdateUniforms(GPU_GEOMETRY_SHADER);
 }
@@ -297,3 +315,18 @@ void C3D_BindProgram(shaderProgram_s* program)
 	else
 		C3Di_ClearShaderUniforms(GPU_GEOMETRY_SHADER);
 }
+
+C3D_FVec* C3D_FixedAttribGetWritePtr(int id)
+{
+	if (id < 0 || id >= 12)
+		return NULL;
+
+	C3D_Context* ctx = C3Di_GetContext();
+
+	if (!(ctx->flags & C3DiF_Active))
+		return NULL;
+
+	ctx->fixedAttribDirty     |= BIT(id);
+	ctx->fixedAttribEverDirty |= BIT(id);
+	return &ctx->fixedAttribs[id];
+}

source/context.h

@@ -44,6 +44,9 @@ typedef struct
 	u32 viewport[5];
 	u32 scissor[3];
 
+	u16 fixedAttribDirty, fixedAttribEverDirty;
+	C3D_FVec fixedAttribs[12];
+
 } C3D_Context;
 
 enum