61 lines
1.8 KiB
GLSL
61 lines
1.8 KiB
GLSL
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vec4 cubicCatmullrom(float x) {
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const float s = 0.5;
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float x2 = x * x;
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float x3 = x2 * x;
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vec4 w;
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w.x = -s*x3 + 2*s*x2 - s*x + 0;
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w.y = (2-s)*x3 + (s-3)*x2 + 1;
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w.z = (s-2)*x3 + (3-2*s)*x2 + s*x + 0;
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w.w = s*x3 - s*x2 + 0;
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return w;
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}
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vec4 cubic(float v) {
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vec4 n = vec4(1.0, 2.0, 3.0, 4.0) - v;
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vec4 s = n * n * n;
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float x = s.x;
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float y = s.y - 4.0 * s.x;
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float z = s.z - 4.0 * s.y + 6.0 * s.x;
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float w = 6.0 - x - y - z;
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return vec4(x, y, z, w) * (1.0/6.0);
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}
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vec3 textureBicubic(sampler2D tex, vec2 tc, vec2 texStep) {
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// http://www.java-gaming.org/index.php?topic=35123.0
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vec2 texSize = 1.0 / texStep;
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tc = tc * texSize - 0.5;
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vec2 fxy = fract(tc);
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tc -= fxy;
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vec4 xcubic = cubic(fxy.x);
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vec4 ycubic = cubic(fxy.y);
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vec4 c = tc.xxyy + vec2(-0.5, 1.5).xyxy;
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vec4 s = vec4(xcubic.xz + xcubic.yw, ycubic.xz + ycubic.yw);
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vec4 offset = c + vec4 (xcubic.yw, ycubic.yw) / s;
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offset *= texStep.xxyy;
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vec3 sample0 = texture(tex, offset.xz).rgb;
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vec3 sample1 = texture(tex, offset.yz).rgb;
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vec3 sample2 = texture(tex, offset.xw).rgb;
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vec3 sample3 = texture(tex, offset.yw).rgb;
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float sx = s.x / (s.x + s.y);
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float sy = s.z / (s.z + s.w);
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return mix(mix(sample3, sample2, sx), mix(sample1, sample0, sx), sy);
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}
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vec4 textureSS(sampler2D tex, vec2 tc, vec2 texStep) {
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vec4 col = texture(tex, tc);
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col += texture(tex, tc + vec2(1.5, 0.0) * texStep);
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col += texture(tex, tc + vec2(-1.5, 0.0) * texStep);
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col += texture(tex, tc + vec2(0.0, 1.5) * texStep);
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col += texture(tex, tc + vec2(0.0, -1.5) * texStep);
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col += texture(tex, tc + vec2(1.5, 1.5) * texStep);
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col += texture(tex, tc + vec2(-1.5, -1.5) * texStep);
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col += texture(tex, tc + vec2(1.5, -1.5) * texStep);
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col += texture(tex, tc + vec2(-1.5, 1.5) * texStep);
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return col / 9.0;
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}
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