29 lines
750 B
Plaintext
29 lines
750 B
Plaintext
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#version 330
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/* A fragment shader: Grayscale Filter with Alpha Exclusion */
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precision highp float; // High quality
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// Draw directly to the screen rather than to an off-screen framebuffer
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layout(location = 0) out vec4 colorOut;
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uniform sampler2D sampler; // Texture sampler
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uniform float alphaCutOff; // Alpha values below this get discarded
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in vec3 texCoord;
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void main(void)
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{
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vec4 texColor = texture(sampler, texCoord.xy);
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if(texColor.a < alphaCutOff)
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discard;
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// Grayscale intensity = Average of a pixel's RGB components
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float intensity = (texColor.r + texColor.g + texColor.b) / 3.0;
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// Output the fragment
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colorOut = vec4(intensity, intensity, intensity, texColor.a);
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const int numViewports = gl_MaxViewports; // Error line
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}
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