commit fca4c34

licar taught me

  1@@ -15,6 +15,8 @@
  2 #define S3L_MAX_HEIGHT (4096)
  3 
  4 #define S3L_MAX_PIXELS (S3L_MAX_WIDTH * S3L_MAX_HEIGHT)
  5+#define S3L_PERSPECTIVE_CORRECTION 2
  6+#define S3L_NEAR_CROSS_STRATEGY 1
  7 #define S3L_Z_BUFFER 1
  8 #define S3L_PIXEL_FUNCTION small3dlib_pixel
  9 #include <small3dlib.h>
 10@@ -48,6 +50,8 @@ typedef struct {
 11 
 12 	RendererMesh*    active_mesh;
 13 	RendererTexture* active_texture;
 14+	u32              active_triangle;
 15+	i32              tri_uvs[6];
 16 } RendererState;
 17 
 18 typedef struct {
 19@@ -194,11 +198,12 @@ static S3L_Vec4 clip_to_screen(const ClipVertex* v)
 20 	float inv_w = 1.0f / v->w;
 21 	float ndc_x = v->x * inv_w;
 22 	float ndc_y = v->y * inv_w;
 23-	float ndc_z = v->z * inv_w;
 24 
 25 	r.x = (S3L_Unit)((ndc_x * 0.5f + 0.5f) * (float)(ren.width - 1));
 26 	r.y = (S3L_Unit)((0.5f - ndc_y * 0.5f) * (float)(ren.height - 1));
 27-	r.z = (S3L_Unit)((ndc_z * 0.5f + 0.5f) * 1048576.0f) + 1;
 28+	r.z = (S3L_Unit)(v->w * (float)S3L_F);
 29+	if (r.z < 1)
 30+		r.z = 1;
 31 	r.w = S3L_F;
 32 
 33 	return r;
 34@@ -206,15 +211,9 @@ static S3L_Vec4 clip_to_screen(const ClipVertex* v)
 35 
 36 static u32 sample_texture(const RendererMesh* mesh, const RendererTexture* texture, const S3L_PixelInfo* pixel)
 37 {
 38-	u32 tri = (u32)pixel->triangleIndex * 3;
 39-	const MGVertex* a = &mesh->vtc[mesh->idc[tri + 0]];
 40-	const MGVertex* b = &mesh->vtc[mesh->idc[tri + 1]];
 41-	const MGVertex* c = &mesh->vtc[mesh->idc[tri + 2]];
 42-	float ba = (float)pixel->barycentric[0] / (float)S3L_F;
 43-	float bb = (float)pixel->barycentric[1] / (float)S3L_F;
 44-	float bc = (float)pixel->barycentric[2] / (float)S3L_F;
 45-	float u = a->u * ba + b->u * bb + c->u * bc;
 46-	float v = a->v * ba + b->v * bb + c->v * bc;
 47+	u32 tri;
 48+	const MGVertex* v[3];
 49+	int barycentric[3];
 50 	i32 x;
 51 	i32 y;
 52 	u8* texel;
 53@@ -222,17 +221,40 @@ static u32 sample_texture(const RendererMesh* mesh, const RendererTexture* textu
 54 	if (!texture || !texture->pixels)
 55 		return 0xffffffff;
 56 
 57-	while (u < 0.0f)
 58-		u += 1.0f;
 59-	while (v < 0.0f)
 60-		v += 1.0f;
 61-	while (u >= 1.0f)
 62-		u -= 1.0f;
 63-	while (v >= 1.0f)
 64-		v -= 1.0f;
 65+	if (ren.active_triangle != (u32)pixel->triangleIndex) {
 66+		ren.active_triangle = pixel->triangleIndex;
 67+		tri = (u32)pixel->triangleIndex * 3;
 68+		v[0] = &mesh->vtc[mesh->idc[tri + 0]];
 69+		v[1] = &mesh->vtc[mesh->idc[tri + 1]];
 70+		v[2] = &mesh->vtc[mesh->idc[tri + 2]];
 71+
 72+		ren.tri_uvs[0] = (i32)(v[0]->u * (float)texture->width);
 73+		ren.tri_uvs[1] = (i32)(v[0]->v * (float)texture->height);
 74+		ren.tri_uvs[2] = (i32)(v[1]->u * (float)texture->width);
 75+		ren.tri_uvs[3] = (i32)(v[1]->v * (float)texture->height);
 76+		ren.tri_uvs[4] = (i32)(v[2]->u * (float)texture->width);
 77+		ren.tri_uvs[5] = (i32)(v[2]->v * (float)texture->height);
 78+	}
 79 
 80-	x = (i32)(u * (float)texture->width);
 81-	y = (i32)(v * (float)texture->height);
 82+	/*licar taught me*/
 83+	/*https://en.wikipedia.org/wiki/Barycentric_coordinate_system*/
 84+	barycentric[0] = pixel->barycentric[0] / 8;
 85+	barycentric[1] = pixel->barycentric[1] / 8;
 86+	barycentric[2] = pixel->barycentric[2] / 8;
 87+
 88+	x = (barycentric[0] * ren.tri_uvs[0] +
 89+	     barycentric[1] * ren.tri_uvs[2] +
 90+	     barycentric[2] * ren.tri_uvs[4]) / (S3L_F / 8);
 91+	y = (barycentric[0] * ren.tri_uvs[1] +
 92+	     barycentric[1] * ren.tri_uvs[3] +
 93+	     barycentric[2] * ren.tri_uvs[5]) / (S3L_F / 8);
 94+
 95+	x %= texture->width;
 96+	y %= texture->height;
 97+	if (x < 0)
 98+		x += texture->width;
 99+	if (y < 0)
100+		y += texture->height;
101 
102 	texel = texture->pixels + ((y * texture->width + x) * 4);
103 	return ((u32)texel[0]) |
104@@ -257,6 +279,7 @@ void renderer_backend_create(MGContext* ctx)
105 	ren.pass = 0;
106 	ren.active_mesh = NULL;
107 	ren.active_texture = NULL;
108+	ren.active_triangle = (u32)-1;
109 }
110 
111 void renderer_backend_begin(void)
112@@ -309,6 +332,7 @@ void renderer_backend_destroy(void)
113 	ren.ctx = NULL;
114 	ren.active_mesh = NULL;
115 	ren.active_texture = NULL;
116+	ren.active_triangle = (u32)-1;
117 	ren.pass = 0;
118 }
119 
120@@ -376,6 +400,7 @@ void renderer_backend_mesh_draw(MGMesh mesh, MGTexture texture, const MGMat4* mv
121 
122 	ren.active_mesh = rmesh;
123 	ren.active_texture = rtexture;
124+	ren.active_triangle = (u32)-1;
125 
126 	for (tri = 0; tri < rmesh->ic; tri += 3) {
127 		ClipVertex ca;
128@@ -403,6 +428,7 @@ void renderer_backend_mesh_draw(MGMesh mesh, MGTexture texture, const MGMat4* mv
129 
130 	ren.active_mesh = NULL;
131 	ren.active_texture = NULL;
132+	ren.active_triangle = (u32)-1;
133 }
134 
135 void renderer_backend_mesh_destroy(MGMesh id)