88 lines
2.5 KiB
Objective-C
Executable File
88 lines
2.5 KiB
Objective-C
Executable File
#import "GPUImageHistogramGenerator.h"
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NSString *const kGPUImageHistogramGeneratorVertexShaderString = SHADER_STRING
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(
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attribute vec4 position;
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attribute vec4 inputTextureCoordinate;
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varying vec2 textureCoordinate;
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varying float height;
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void main()
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{
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gl_Position = position;
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textureCoordinate = vec2(inputTextureCoordinate.x, 0.5);
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height = 1.0 - inputTextureCoordinate.y;
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}
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);
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#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
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NSString *const kGPUImageHistogramGeneratorFragmentShaderString = SHADER_STRING
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(
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varying highp vec2 textureCoordinate;
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varying highp float height;
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uniform sampler2D inputImageTexture;
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uniform lowp vec4 backgroundColor;
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void main()
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{
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lowp vec3 colorChannels = texture2D(inputImageTexture, textureCoordinate).rgb;
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lowp vec4 heightTest = vec4(step(height, colorChannels), 1.0);
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gl_FragColor = mix(backgroundColor, heightTest, heightTest.r + heightTest.g + heightTest.b);
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}
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);
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#else
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NSString *const kGPUImageHistogramGeneratorFragmentShaderString = SHADER_STRING
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(
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varying vec2 textureCoordinate;
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varying float height;
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uniform sampler2D inputImageTexture;
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uniform vec4 backgroundColor;
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void main()
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{
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vec3 colorChannels = texture2D(inputImageTexture, textureCoordinate).rgb;
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vec4 heightTest = vec4(step(height, colorChannels), 1.0);
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gl_FragColor = mix(backgroundColor, heightTest, heightTest.r + heightTest.g + heightTest.b);
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}
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);
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#endif
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@implementation GPUImageHistogramGenerator
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#pragma mark -
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#pragma mark Initialization and teardown
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- (id)init;
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{
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if (!(self = [super initWithVertexShaderFromString:kGPUImageHistogramGeneratorVertexShaderString fragmentShaderFromString:kGPUImageHistogramGeneratorFragmentShaderString]))
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{
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return nil;
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}
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backgroundColorUniform = [filterProgram uniformIndex:@"backgroundColor"];
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[self setBackgroundColorRed:0.0 green:0.0 blue:0.0 alpha:0.0];
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return self;
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}
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#pragma mark -
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#pragma mark Accessors
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- (void)setBackgroundColorRed:(GLfloat)redComponent green:(GLfloat)greenComponent blue:(GLfloat)blueComponent alpha:(GLfloat)alphaComponent;
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{
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// GLfloat backgroundColor[4];
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// backgroundColor[0] = redComponent;
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// backgroundColor[1] = greenComponent;
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// backgroundColor[2] = blueComponent;
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// backgroundColor[3] = alphaComponent;
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GPUVector4 backgroundColor = {redComponent, greenComponent, blueComponent, alphaComponent};
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[self setVec4:backgroundColor forUniform:backgroundColorUniform program:filterProgram];
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}
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@end
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