minetest/client/shaders/nodes_shader/opengl_fragment.glsl

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uniform sampler2D baseTexture;
uniform sampler2D normalTexture;
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uniform sampler2D textureFlags;
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 float area_enable_parallax;
varying vec3 eyeVec;
varying vec3 tsEyeVec;
varying vec3 lightVec;
varying vec3 tsLightVec;
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bool normalTexturePresent = false;
const float e = 2.718281828459;
const float BS = 10.0;
const float fogStart = FOG_START;
const float fogShadingParameter = 1 / ( 1 - fogStart);
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#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)
{
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return ((x * (0.22 * x + 0.03) + 0.002) / (x * (0.22 * x + 0.3) + 0.06)) - 0.03333;
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}
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
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void get_texture_flags()
{
vec4 flags = texture2D(textureFlags, vec2(0.0, 0.0));
if (flags.r > 0.5) {
normalTexturePresent = true;
}
}
vec4 get_normal_map(vec2 uv)
{
vec4 bump = texture2D(normalTexture, uv).rgba;
bump.xyz = normalize(bump.xyz * 2.0 - 1.0);
return bump;
}
float find_intersection(vec2 dp, vec2 ds)
{
float depth = 1.0;
float best_depth = 0.0;
float size = 0.0625;
for (int i = 0; i < 15; i++) {
depth -= size;
float h = texture2D(normalTexture, dp + ds * depth).a;
if (depth <= h) {
best_depth = depth;
break;
}
}
depth = best_depth;
for (int i = 0; i < 4; i++) {
size *= 0.5;
float h = texture2D(normalTexture,dp + ds * depth).a;
if (depth <= h) {
best_depth = depth;
depth += size;
} else {
depth -= size;
}
}
return best_depth;
}
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void main(void)
{
vec3 color;
vec4 bump;
vec2 uv = gl_TexCoord[0].st;
bool use_normalmap = false;
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get_texture_flags();
#ifdef ENABLE_PARALLAX_OCCLUSION
vec2 eyeRay = vec2 (tsEyeVec.x, -tsEyeVec.y);
const float scale = PARALLAX_OCCLUSION_SCALE / PARALLAX_OCCLUSION_ITERATIONS;
const float bias = PARALLAX_OCCLUSION_BIAS / PARALLAX_OCCLUSION_ITERATIONS;
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#if PARALLAX_OCCLUSION_MODE == 0
// Parallax occlusion with slope information
if (normalTexturePresent && area_enable_parallax > 0.0) {
for (int i = 0; i < PARALLAX_OCCLUSION_ITERATIONS; i++) {
vec4 normal = texture2D(normalTexture, uv.xy);
float h = normal.a * scale - bias;
uv += h * normal.z * eyeRay;
}
}
#endif
#if PARALLAX_OCCLUSION_MODE == 1
// Relief mapping
if (normalTexturePresent && area_enable_parallax > 0.0) {
vec2 ds = eyeRay * PARALLAX_OCCLUSION_SCALE;
float dist = find_intersection(uv, ds);
uv += dist * ds;
}
#endif
#endif
#if USE_NORMALMAPS == 1
if (normalTexturePresent) {
bump = get_normal_map(uv);
use_normalmap = true;
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}
#endif
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.
if (base.a == 0.0) {
discard;
}
#endif
#ifdef ENABLE_BUMPMAPPING
if (use_normalmap) {
vec3 L = normalize(lightVec);
vec3 E = normalize(eyeVec);
float specular = pow(clamp(dot(reflect(L, bump.xyz), E), 0.0, 1.0), 1.0);
float diffuse = dot(-E,bump.xyz);
color = (diffuse + 0.1 * specular) * base.rgb;
} else {
color = base.rgb;
}
#else
color = base.rgb;
#endif
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vec4 col = vec4(color.rgb * gl_Color.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);
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col = vec4(col.rgb, base.a);
gl_FragColor = col;
}