Fix unexplained shader issue (glsl compiler bug??) (#4757)

This commit is contained in:
Rogier-5 2016-11-16 17:56:05 +01:00 committed by Zeno-
parent 8e61c1dfd9
commit 5f0dc8e78a
3 changed files with 42 additions and 6 deletions

@ -19,6 +19,8 @@ bool normalTexturePresent = false;
const float e = 2.718281828459;
const float BS = 10.0;
const float fogStart = 0.4;
const float fogShadingParameter = 1 / ( 1 - fogStart);
#ifdef ENABLE_TONE_MAPPING
@ -199,8 +201,18 @@ void main(void)
#endif
if (fogDistance != 0.0) {
float d = clamp((fogDistance - length(eyeVec)) / (fogDistance * 0.6), 0.0, 1.0);
col = mix(skyBgColor, col, d);
// Due to a bug in some (older ?) graphics stacks (possibly in the glsl compiler ?),
// the fog will only be rendered correctly if the last operation before the
// clamp() is an addition. Else, the clamp() seems to be ignored.
// E.g. the following won't work:
// float clarity = clamp(fogShadingParameter
// * (fogDistance - length(eyeVec)) / fogDistance), 0.0, 1.0);
// As additions usually come for free following a multiplication, the new formula
// should be more efficient as well.
// Note: clarity = (1 - fogginess)
float clarity = clamp(fogShadingParameter
- fogShadingParameter * length(eyeVec) / fogDistance, 0.0, 1.0);
col = mix(skyBgColor, col, clarity);
}
col = vec4(col.rgb, base.a);

@ -21,6 +21,8 @@ bool texSeamless = false;
const float e = 2.718281828459;
const float BS = 10.0;
const float fogStart = 0.4;
const float fogShadingParameter = 1 / ( 1 - fogStart);
#ifdef ENABLE_TONE_MAPPING
@ -155,8 +157,18 @@ vec4 base = texture2D(baseTexture, uv).rgba;
#endif
if (fogDistance != 0.0) {
float d = clamp((fogDistance - length(eyeVec)) / (fogDistance * 0.6), 0.0, 1.0);
col = mix(skyBgColor, col, d);
// Due to a bug in some (older ?) graphics stacks (possibly in the glsl compiler ?),
// the fog will only be rendered correctly if the last operation before the
// clamp() is an addition. Else, the clamp() seems to be ignored.
// E.g. the following won't work:
// float clarity = clamp(fogShadingParameter
// * (fogDistance - length(eyeVec)) / fogDistance), 0.0, 1.0);
// As additions usually come for free following a multiplication, the new formula
// should be more efficient as well.
// Note: clarity = (1 - fogginess)
float clarity = clamp(fogShadingParameter
- fogShadingParameter * length(eyeVec) / fogDistance, 0.0, 1.0);
col = mix(skyBgColor, col, clarity);
}
col = vec4(col.rgb, base.a);

@ -19,6 +19,8 @@ bool texSeamless = false;
const float e = 2.718281828459;
const float BS = 10.0;
const float fogStart = 0.4;
const float fogShadingParameter = 1 / ( 1 - fogStart);
void get_texture_flags()
{
@ -107,8 +109,18 @@ void main(void)
vec4 col = vec4(color.rgb, base.a);
col *= gl_Color;
if (fogDistance != 0.0) {
float d = clamp((fogDistance - length(eyeVec)) / (fogDistance * 0.6), 0.0, 1.0);
col = mix(skyBgColor, col, d);
// Due to a bug in some (older ?) graphics stacks (possibly in the glsl compiler ?),
// the fog will only be rendered correctly if the last operation before the
// clamp() is an addition. Else, the clamp() seems to be ignored.
// E.g. the following won't work:
// float clarity = clamp(fogShadingParameter
// * (fogDistance - length(eyeVec)) / fogDistance), 0.0, 1.0);
// As additions usually come for free following a multiplication, the new formula
// should be more efficient as well.
// Note: clarity = (1 - fogginess)
float clarity = clamp(fogShadingParameter
- fogShadingParameter * length(eyeVec) / fogDistance, 0.0, 1.0);
col = mix(skyBgColor, col, clarity);
}
gl_FragColor = vec4(col.rgb, base.a);
}