#import "GPUImageLineGenerator.h"
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NSString *const kGPUImageLineGeneratorVertexShaderString = SHADER_STRING
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(
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attribute vec4 position;
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void main()
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{
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gl_Position = position;
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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 kGPUImageLineGeneratorFragmentShaderString = SHADER_STRING
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(
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uniform lowp vec3 lineColor;
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void main()
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{
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gl_FragColor = vec4(lineColor, 1.0);
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}
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);
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#else
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NSString *const kGPUImageLineGeneratorFragmentShaderString = SHADER_STRING
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(
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uniform vec3 lineColor;
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void main()
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{
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gl_FragColor = vec4(lineColor, 1.0);
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}
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);
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#endif
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@interface GPUImageLineGenerator()
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- (void)generateLineCoordinates;
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@end
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@implementation GPUImageLineGenerator
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@synthesize lineWidth = _lineWidth;
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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:kGPUImageLineGeneratorVertexShaderString fragmentShaderFromString:kGPUImageLineGeneratorFragmentShaderString]))
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{
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return nil;
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}
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runSynchronouslyOnVideoProcessingQueue(^{
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lineWidthUniform = [filterProgram uniformIndex:@"lineWidth"];
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lineColorUniform = [filterProgram uniformIndex:@"lineColor"];
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self.lineWidth = 1.0;
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[self setLineColorRed:0.0 green:1.0 blue:0.0];
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});
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return self;
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}
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- (void)dealloc
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{
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if (lineCoordinates)
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{
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free(lineCoordinates);
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}
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}
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#pragma mark -
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#pragma mark Rendering
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- (void)generateLineCoordinates;
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{
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lineCoordinates = calloc(1024 * 4, sizeof(GLfloat));
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}
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- (void)renderLinesFromArray:(GLfloat *)lineSlopeAndIntercepts count:(NSUInteger)numberOfLines frameTime:(CMTime)frameTime;
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{
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if (self.preventRendering)
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{
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return;
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}
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if (lineCoordinates == NULL)
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{
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[self generateLineCoordinates];
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}
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// Iterate through and generate vertices from the slopes and intercepts
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NSUInteger currentVertexIndex = 0;
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NSUInteger currentLineIndex = 0;
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NSUInteger maxLineIndex = numberOfLines *2;
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while(currentLineIndex < maxLineIndex)
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{
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GLfloat slope = lineSlopeAndIntercepts[currentLineIndex++];
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GLfloat intercept = lineSlopeAndIntercepts[currentLineIndex++];
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if (slope > 9000.0) // Vertical line
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{
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lineCoordinates[currentVertexIndex++] = intercept;
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lineCoordinates[currentVertexIndex++] = -1.0;
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lineCoordinates[currentVertexIndex++] = intercept;
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lineCoordinates[currentVertexIndex++] = 1.0;
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}
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else
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{
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lineCoordinates[currentVertexIndex++] = -1.0;
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lineCoordinates[currentVertexIndex++] = slope * -1.0 + intercept;
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lineCoordinates[currentVertexIndex++] = 1.0;
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lineCoordinates[currentVertexIndex++] = slope * 1.0 + intercept;
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}
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}
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runSynchronouslyOnVideoProcessingQueue(^{
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[GPUImageContext setActiveShaderProgram:filterProgram];
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outputFramebuffer = [[GPUImageContext sharedFramebufferCache] fetchFramebufferForSize:[self sizeOfFBO] textureOptions:self.outputTextureOptions onlyTexture:NO];
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[outputFramebuffer activateFramebuffer];
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glClearColor(0.0, 0.0, 0.0, 0.0);
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glClear(GL_COLOR_BUFFER_BIT);
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glBlendEquation(GL_FUNC_ADD);
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glBlendFunc(GL_ONE, GL_ONE);
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glEnable(GL_BLEND);
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glVertexAttribPointer(filterPositionAttribute, 2, GL_FLOAT, 0, 0, lineCoordinates);
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glDrawArrays(GL_LINES, 0, ((unsigned int)numberOfLines * 2));
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glDisable(GL_BLEND);
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[self informTargetsAboutNewFrameAtTime:frameTime];
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});
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}
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- (void)renderToTextureWithVertices:(const GLfloat *)vertices textureCoordinates:(const GLfloat *)textureCoordinates;
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{
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// Prevent rendering of the frame by normal means
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}
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#pragma mark -
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#pragma mark Accessors
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- (void)setLineWidth:(CGFloat)newValue;
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{
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_lineWidth = newValue;
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[GPUImageContext setActiveShaderProgram:filterProgram];
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glLineWidth(newValue);
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}
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- (void)setLineColorRed:(GLfloat)redComponent green:(GLfloat)greenComponent blue:(GLfloat)blueComponent;
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{
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GPUVector3 lineColor = {redComponent, greenComponent, blueComponent};
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[self setVec3:lineColor forUniform:lineColorUniform program:filterProgram];
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}
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@end
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