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fgdata/Shaders/ws30-q1.frag
Stuart Buchanan 580c375d4b WS30: Use perlin texture to reduce tiling
Use a perlin noise texture to rotate some of the landclass
textures to reduce tiling.

Also add a quality=1 technique which uses it.
2021-01-26 20:17:17 +00:00

65 lines
2.1 KiB
C++

// WS30 FRAGMENT SHADER
// -*-C++-*-
#version 130
#extension GL_EXT_texture_array : enable
varying vec3 normal;
uniform sampler2D landclass;
uniform sampler2DArray atlas;
uniform sampler1D dimensionsArray;
uniform sampler1D diffuseArray;
uniform sampler1D specularArray;
uniform sampler2D perlin;
// Passed from VPBTechnique, not the Effect
uniform float tile_width;
uniform float tile_height;
// See include_fog.frag
uniform int fogType;
vec3 fog_Func(vec3 color, int type);
void main()
{
vec3 lightDir = gl_LightSource[0].position.xyz;
vec3 halfVector = gl_LightSource[0].halfVector.xyz;
vec4 texel;
vec4 fragColor;
// The Landclass for this particular fragment. This can be used to
// index into the atlas textures.
int lc = int(texture2D(landclass, gl_TexCoord[0].st).g * 255.0 + 0.5);
// If gl_Color.a == 0, this is a back-facing polygon and the
// normal should be reversed.
vec3 n = (2.0 * gl_Color.a - 1.0) * normal;
n = normalize(n);
float NdotL = dot(n, lightDir);
float NdotHV = max(dot(n, halfVector), 0.0);
// Different textures have different have different dimensions.
// Dimensions array is scaled to fit in [0...1.0] in the texture1D, so has to be scaled back up here.
vec4 color = texture(diffuseArray, float(lc)/512.0) * NdotL;
vec4 specular = texture(specularArray, float(lc)/512.0);
vec2 atlas_dimensions = 10000.0 * texture(dimensionsArray, float(lc)/512.0).st;
vec2 atlas_scale = vec2(tile_width / atlas_dimensions.s, tile_height / atlas_dimensions.t );
vec2 st = atlas_scale * gl_TexCoord[0].st;
// Rotate texture using the perlin texture as a mask to reduce tiling
if (step(0.5, texture(perlin, atlas_scale * gl_TexCoord[0].st / 8.0).r) == 1.0) {
st = vec2(atlas_scale.s * gl_TexCoord[0].t, atlas_scale.t * gl_TexCoord[0].s);
}
if (step(0.5, texture(perlin, - atlas_scale * gl_TexCoord[0].st / 16.0).r) == 1.0) {
st = -st;
}
texel = texture(atlas, vec3(st, lc));
fragColor = texel + pow(NdotHV, gl_FrontMaterial.shininess) * gl_LightSource[0].specular * specular;
fragColor.rgb = fog_Func(fragColor.rgb, fogType);
gl_FragColor = fragColor;
}