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uniform sampler2D baseTexture;
uniform vec4 skyBgColor;
uniform float fogDistance;
uniform vec3 eyePosition;
// The cameraOffset is the current center of the visible world.
uniform vec3 cameraOffset;
uniform float animationTimer;
varying vec3 vPosition;
// World position in the visible world (i.e. relative to the cameraOffset.)
// This can be used for many shader effects without loss of precision.
// If the absolute position is required it can be calculated with
// cameraOffset + worldPosition (for large coordinates the limits of float
// precision must be considered).
varying vec3 worldPosition;
varying lowp vec4 varColor;
centroid varying mediump vec2 varTexCoord;
varying vec3 eyeVec;
const float fogStart = FOG_START;
const float fogShadingParameter = 1.0 / ( 1.0 - fogStart);
#ifdef ENABLE_TONE_MAPPING
/* Hable's UC2 Tone mapping parameters
A = 0.22;
B = 0.30;
C = 0.10;
D = 0.20;
E = 0.01;
F = 0.30;
W = 11.2;
equation used: ((x * (A * x + C * B) + D * E) / (x * (A * x + B) + D * F)) - E / F
*/
vec3 uncharted2Tonemap(vec3 x)
{
return ((x * (0.22 * x + 0.03) + 0.002) / (x * (0.22 * x + 0.3) + 0.06)) - 0.03333;
}
vec4 applyToneMapping(vec4 color)
{
color = vec4(pow(color.rgb, vec3(2.2)), color.a);
const float gamma = 1.6;
const float exposureBias = 5.5;
color.rgb = uncharted2Tonemap(exposureBias * color.rgb);
// Precalculated white_scale from
//vec3 whiteScale = 1.0 / uncharted2Tonemap(vec3(W));
vec3 whiteScale = vec3(1.036015346);
color.rgb *= whiteScale;
return vec4(pow(color.rgb, vec3(1.0 / gamma)), color.a);
}
#endif
void main(void)
{
vec3 color;
vec2 uv = varTexCoord.st;
vec4 base = texture2D(baseTexture, uv).rgba;
#ifdef USE_DISCARD
// If alpha is zero, we can just discard the pixel. This fixes transparency
// on GPUs like GC7000L, where GL_ALPHA_TEST is not implemented in mesa,
// and also on GLES 2, where GL_ALPHA_TEST is missing entirely.
if (base.a == 0.0) {
discard;
}
#endif
color = base.rgb;
vec4 col = vec4(color.rgb * varColor.rgb, 1.0);
#ifdef ENABLE_TONE_MAPPING
col = applyToneMapping(col);
#endif
// 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);
gl_FragColor = col;
}
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