Add alpha blending of transparent textures
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abf9e8fa7c
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ba68f22bee
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FD6B27654AF5E348
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@ -64,7 +64,7 @@ int EngineInit(char *objFilename, char *mtlFilename)
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// Mesh configuration
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mesh.position.z = 175;
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mesh.position.z = 50;
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mesh.position.y = -175;
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mesh.scale = 1.0f;
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@ -152,29 +152,29 @@ static void CheckInputs(uint32_t input)
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if (CHECK_BIT(input, ROTATE_X_POS))
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{
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mesh.position.x += 10;
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mesh.rotation.x += 0.10f;
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}
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else if (CHECK_BIT(input, ROTATE_X_NEG))
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{
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mesh.position.x -= 10;
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mesh.rotation.x -= 0.10f;
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}
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if (CHECK_BIT(input, ROTATE_Y_POS))
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{
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mesh.position.y += 10;
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mesh.rotation.y += 0.10f;
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}
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else if (CHECK_BIT(input, ROTATE_Y_NEG))
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{
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mesh.position.y -= 10;
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mesh.rotation.y -= 0.10f;
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}
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if (CHECK_BIT(input, ROTATE_Z_POS))
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{
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mesh.position.z += 10;
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mesh.rotation.z += 0.10f;
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}
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else if (CHECK_BIT(input, ROTATE_Z_NEG))
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{
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mesh.position.z -= 10;
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mesh.rotation.z -= 0.10f;
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}
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if (CHECK_BIT(input, SCALE_UP))
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@ -8,7 +8,7 @@
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// STATIC PROTOTYPES
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static int LoadTexture(char *filename, Texture &texture);
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static int LoadTexture(char *filename, Texture &texture, float opacity);
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#pragma pack(push, 1)
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@ -194,7 +194,9 @@ int ParseMTL(char *filename, EngineMemory &memory)
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{
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char *textureFilename = data;
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textureFilename[strcspn(textureFilename, "\r\n")] = 0;
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LoadTexture(textureFilename, textures.data[materialIndex]);
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LoadTexture(
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textureFilename, textures.data[materialIndex],
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materials.data[materialIndex].opacity);
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}
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}
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}
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@ -204,7 +206,7 @@ int ParseMTL(char *filename, EngineMemory &memory)
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return 0;
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}
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static int LoadTexture(char *filename, Texture &texture)
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static int LoadTexture(char *filename, Texture &texture, float opacity)
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{
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FILE *fp = fopen(filename, "r");
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if (fp == NULL)
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@ -227,6 +229,7 @@ static int LoadTexture(char *filename, Texture &texture)
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fread(&texture.texels[y][x].b, 1, 1, fp);
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fread(&texture.texels[y][x].g, 1, 1, fp);
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fread(&texture.texels[y][x].r, 1, 1, fp);
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texture.texels[y][x].a = (uint8_t)(255 * opacity);
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}
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// Discard padding byte
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@ -114,24 +114,32 @@ void Render(EngineBuffer &buffer, EngineMemory &memory)
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float duDiff = 1 - du;
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float dvDiff = 1 - dv;
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ColorU32 color;
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color.b = (uint8_t)
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(duDiff * dvDiff * texture.texels[v][u].b
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+ du * dvDiff * texture.texels[v][u+1].b
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+ du * dv * texture.texels[v+1][u+1].b
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+ duDiff * dv * texture.texels[v+1][u].b);
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ColorU32 color =
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{
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(uint8_t)
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(duDiff * dvDiff * texture.texels[v][u].b
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+ du * dvDiff * texture.texels[v][u+1].b
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+ du * dv * texture.texels[v+1][u+1].b
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+ duDiff * dv * texture.texels[v+1][u].b),
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color.g = (uint8_t)
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(duDiff * dvDiff * texture.texels[v][u].g
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+ du * dvDiff * texture.texels[v][u+1].g
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+ du * dv * texture.texels[v+1][u+1].g
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+ duDiff * dv * texture.texels[v+1][u].g);
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(uint8_t)
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(duDiff * dvDiff * texture.texels[v][u].g
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+ du * dvDiff * texture.texels[v][u+1].g
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+ du * dv * texture.texels[v+1][u+1].g
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+ duDiff * dv * texture.texels[v+1][u].g),
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color.r = (uint8_t)
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(duDiff * dvDiff * texture.texels[v][u].r
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+ du * dvDiff * texture.texels[v][u+1].r
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+ du * dv * texture.texels[v+1][u+1].r
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+ duDiff * dv * texture.texels[v+1][u].r);
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(uint8_t)
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(duDiff * dvDiff * texture.texels[v][u].r
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+ du * dvDiff * texture.texels[v][u+1].r
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+ du * dv * texture.texels[v+1][u+1].r
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+ duDiff * dv * texture.texels[v+1][u].r),
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(uint8_t)
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(duDiff * dvDiff * texture.texels[v][u].a
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+ du * dvDiff * texture.texels[v][u+1].a
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+ du * dv * texture.texels[v+1][u+1].a
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+ duDiff * dv * texture.texels[v+1][u].a)
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};
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// Perform Gouraud shading on the texture
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@ -145,7 +153,7 @@ void Render(EngineBuffer &buffer, EngineMemory &memory)
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+ (barycenter[2] * c2);
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// Ensure no color channel exceeds 1.0
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// Ensure no color channel exceeds max
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ScaleColor(shading);
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@ -154,6 +162,7 @@ void Render(EngineBuffer &buffer, EngineMemory &memory)
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color.g *= shading.g;
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color.r *= shading.r;
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// Interpolate 1/z for the z-buffer
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float zInv =
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1.0f /
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@ -165,7 +174,21 @@ void Render(EngineBuffer &buffer, EngineMemory &memory)
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// Draw the pixel if it's closer than what's in the z-buffer
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if (zInv > memory.zbuffer[y][x])
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{
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DrawPixel(buffer.buffer, buffer.width, color.u32, x, y);
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ColorU32 *pixel = (ColorU32*)&buffer.buffer[y*buffer.width+x];
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float alpha = color.a / 255.0f;
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float alphaDiff = 1.0f - alpha;
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// Blend new color with the existing color
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ColorU32 blended =
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{
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(uint8_t)((alpha * color.b) + (alphaDiff * pixel->b)),
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(uint8_t)((alpha * color.g) + (alphaDiff * pixel->g)),
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(uint8_t)((alpha * color.r) + (alphaDiff * pixel->r)),
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(uint8_t)((alpha * color.a) + (alphaDiff * pixel->a))
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};
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DrawPixel(buffer.buffer, buffer.width, blended.u32, x, y);
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memory.zbuffer[y][x] = zInv;
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}
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