gl_shader_gen: use accurate LOD formula for texture 2D

This commit is contained in:
wwylele 2018-07-06 00:59:43 +03:00 committed by Weiyi Wang
parent ca78d34933
commit fa141c799b

View file

@ -317,8 +317,9 @@ static std::string SampleTexture(const PicaFSConfig& config, unsigned texture_un
// Only unit 0 respects the texturing type
switch (state.texture0_type) {
case TexturingRegs::TextureConfig::Texture2D:
return "texture(tex0, texcoord0)";
return "textureLod(tex0, texcoord0, getLod(texcoord0 * textureSize(tex0, 0)))";
case TexturingRegs::TextureConfig::Projection2D:
// TODO (wwylele): find the exact LOD formula for projection texture
return "textureProj(tex0, vec3(texcoord0, texcoord0_w))";
case TexturingRegs::TextureConfig::TextureCube:
return "texture(tex_cube, vec3(texcoord0, texcoord0_w))";
@ -335,12 +336,12 @@ static std::string SampleTexture(const PicaFSConfig& config, unsigned texture_un
return "texture(tex0, texcoord0)";
}
case 1:
return "texture(tex1, texcoord1)";
return "textureLod(tex1, texcoord1, getLod(texcoord1 * textureSize(tex1, 0)))";
case 2:
if (state.texture2_use_coord1)
return "texture(tex2, texcoord1)";
return "textureLod(tex2, texcoord1, getLod(texcoord1 * textureSize(tex2, 0)))";
else
return "texture(tex2, texcoord2)";
return "textureLod(tex2, texcoord2, getLod(texcoord2 * textureSize(tex2, 0)))";
case 3:
if (state.proctex.enable) {
return "ProcTex()";
@ -1333,6 +1334,15 @@ vec4 byteround(vec4 x) {
return round(x * 255.0) * (1.0 / 255.0);
}
// PICA's LOD formula for 2D textures.
// This LOD formula is the same as the LOD lower limit defined in OpenGL.
// f(x, y) >= max{m_u, m_v, m_w}
// (See OpenGL 4.6 spec, 8.14.1 - Scale Factor and Level-of-Detail)
float getLod(vec2 coord) {
vec2 d = max(abs(dFdx(coord)), abs(dFdy(coord)));
return log2(max(d.x, d.y));
}
#if ALLOW_SHADOW
uvec2 DecodeShadow(uint pixel) {