121 lines
2.8 KiB
GLSL
121 lines
2.8 KiB
GLSL
#ifdef GL_ES
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precision mediump float;
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#endif
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uniform mat3 worldToOutput;
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uniform sampler2D inputImage[1];
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uniform mat3 outputToInput[1];
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mat3 worldToInput = outputToInput[0] * worldToOutput;
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uniform float threshold;
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uniform float brightness;
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uniform float radius;
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uniform float angle;
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uniform float halo;
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float det(mat3 m) { return m[0][0] * m[1][1] - m[0][1] * m[1][0]; }
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float scale = sqrt(abs(det(worldToOutput)));
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float angle_ = radians(angle);
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float sin_ = sin(angle_);
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float cos_ = cos(angle_);
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float threshold_ = 1.0 - 0.01 * threshold;
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float rad_ = radius * scale;
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const vec3 lVec = vec3(0.298980712, 0.587036132, 0.113983154);
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#define STEPS_PER_PIXEL 4.0
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float stepsCount = ceil(STEPS_PER_PIXEL * rad_);
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float halo_ = 0.01 * (halo + 1.0) * stepsCount;
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float rayWeight(float s)
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{
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s /= halo_;
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return clamp(1.0 - s * s, 0.0, 1.0);
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}
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vec4 lightValue(const vec2 texCoord)
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{
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vec4 col = texture2D(inputImage[0], texCoord);
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float l = dot(lVec, col.rgb);
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return smoothstep(threshold_, 1.0, l) * col;
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}
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bool filterLine(inout vec4 col, const vec2 p, const vec2 dx, float s_y)
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{
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float rw = rayWeight(s_y);
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if(rw == 0.0)
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return false;
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float dw = max(1.0 - s_y / stepsCount, 0.0);
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col += dw * rw * lightValue(p);
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vec2 s = vec2(0.0, s_y);
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for(s.x = 1.0; s.x < stepsCount; s.x += 1.0)
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{
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dw = max(1.0 - length(s) / stepsCount, 0.0);
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col += rw * dw * (
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lightValue(p + s.x * dx) +
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lightValue(p - s.x * dx));
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}
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return true;
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}
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void main( void )
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{
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vec2 texCoord = (outputToInput[0] * vec3(gl_FragCoord.xy, 1.0)).xy;
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float step = radius / stepsCount;
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mat2 transf =
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mat2((worldToInput * vec3(1.0, 0.0, 0.0)).xy,
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(worldToInput * vec3(0.0, 1.0, 0.0)).xy) * // worldToInput without translational part
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mat2(cos_, sin_, -sin_, cos_) * // angle shift by uniform parameter
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step; // [-stepsCount,stepsCount]^2 to [-radius, radius]^2
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// Filter lines in the 2 orthogonal directions
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vec4 addCol = vec4(0.0);
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// Horizontal
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filterLine(addCol, texCoord, transf[0], 0.0);
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for(float s = 1.0; s < stepsCount; s += 1.0)
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{
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if(!filterLine(addCol, texCoord + s * transf[1], transf[0], s))
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break;
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filterLine(addCol, texCoord - s * transf[1], transf[0], s);
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}
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// Vertical
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filterLine(addCol, texCoord, transf[1], 0.0);
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for(float s = 1.0; s < stepsCount; s += 1.0)
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{
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if(!filterLine(addCol, texCoord + s * transf[0], transf[1], s))
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break;
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filterLine(addCol, texCoord - s * transf[0], transf[1], s);
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}
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float weight = stepsCount * STEPS_PER_PIXEL;
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vec4 col = texture2D(inputImage[0], texCoord);
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gl_FragColor = col + addCol * (brightness / weight);
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}
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