自定義着色器GPUImage和GLKIT IOS

Question

我有自定義着色器需要3 sampler2d統一值，我需要將它們的三個映射如下所示傳遞給每個紋理。我已經創建了代碼，如下所示擴展GPUImage類。

#import "MappingShader.h" 
#import <GLKit/GLKit.h> 
NSString *const kGPUImageAtgMappingFragmentShaderString = SHADER_STRING 
(
precision highp float; 

uniform sampler2D inputImageTexture; 
uniform sampler2D red; 
uniform sampler2D green; 
uniform sampler2D blue; 
uniform float uAmount; 

varying vec2 textureCoordinate; 

void main() { 
    vec4 color = texture2D(inputImageTexture, textureCoordinate); 

    vec2 indexRed = vec2(color.r, 0.0); 
    vec4 redColor = texture2D(red, indexRed); 

    vec2 indexGreen = vec2(color.g, 0.0); 
    vec4 greenColor = texture2D(green, indexGreen); 

    vec2 indexBlue = vec2(color.b, 0.0); 
    vec4 blueColor = texture2D(blue, indexBlue); 

    gl_FragColor = mix(
         color, 
         vec4(redColor.r, greenColor.g, blueColor.b, color.a), 
         uAmount); 
} 
); 

@interface MappingShader() 
{ 
    GLint uAmount, red, green, blue; 
} 
@end 



@implementation MappingShader 

@synthesize amount = _amount; 

- (id)init; 
{ 

    if (!(self = [super initWithFragmentShaderFromString:kGPUImageAtgMappingFragmentShaderString])) 
    { 
     return nil; 
    } 

    red = [filterProgram uniformIndex:@"inputImageTexture"]; 
    green = [filterProgram uniformIndex:@"green"]; 
    blue = [filterProgram uniformIndex:@"blue"]; 

    GLKTextureInfo *redtexr; 
    NSError *error; 
    NSString *filepath = [[NSBundle mainBundle] pathForResource:@"aladin" ofType:@"png"]; 

    redtexr = [GLKTextureLoader textureWithContentsOfFile:filepath options:nil error:&error]; 
    glActiveTexture(GL_TEXTURE0); 
    glUniform1i(red, 0); 
    glBindTexture(GL_TEXTURE_2D, redtexr.name); 

    uAmount = [filterProgram uniformIndex:@"uAmount"]; 

    self.amount = 0.5; 
    return self; 


// glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 300, 300, 0, GL_RGBA, GL_ARRAY_BUFFER, <#const GLvoid *pixels#>) 

// GLKTextureInfo *texs = [GLKTextureLoader alloc] initWithSharegroup:<#(EAGLSharegroup *)#> 
} 

-(void)setAmount:(CGFloat)amount 
{ 
    _amount = amount; 
    [self setFloat:_amount forUniform:uAmount program:filterProgram]; 


} 

@end 

所以請幫助我如何將下面的值傳遞給着色器並獲得結果圖像。我也嘗試過GLKIT加載程序，但無法獲得任何結果。

"red" : [54,54,55,55,55,56,56,57,57,57,58,58,58,59,59,60,60,60,61,61,61,62,62,63,63,63,64,64,65,65,65,66,66,67,67,67,68,68,69,69,69,70,70,71,71,72,72,73,73,73,74,74,75,75,76,76,77,77,78,78,79,79,80,80,81,81,82,82,83,83,84,85,85,86,86,87,87,88,89,89,90,90,91,92,92,93,94,94,95,96,96,97,98,98,99,100,100,101,102,102,103,104,105,105,106,107,107,108,109,110,111,111,112,113,114,114,115,116,117,118,118,119,120,121,122,123,123,124,125,126,127,128,128,129,130,131,132,133,134,135,135,136,137,138,139,140,141,142,143,144,145,146,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,191,192,193,194,195,196,197,198,199,200,201,202,203,204,205,207,208,209,210,211,212,213,214,215,216,217,219,220,221,222,223,224,225,226,227,228,230,231,232,233,234,235,236,237,238,239,241,242,243,244,245,246,247,248,249,251,252,253,254,255], 
        "green" : [0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,160,161,162,163,164,165,166,167,168,169,170,171,171,172,173,174,175,176,177,177,178,179,180,181,181,182,183,184,184,185,186,187,187,188,189,189,190,191,191,192,193,193,194,194,195,195,196,197,197,198,198,199,199,199,200,200,201,201,202,202,202,203,203,203,204,204,204,205,205,205,206,206,206,207,207,207,207,208,208,208,209,209,209,209,209,210,210,210,210,211,211,211,211,212,212,212], 
        "blue" : [0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,61,62,63,64,65,66,67,68,69,70,70,71,72,73,74,75,76,77,77,78,79,80,81,82,82,83,84,85,86,86,87,88,89,89,90,91,92,92,93,94,95,95,96,97,98,98,99,100,100,101,102,102,103,104,104,105,106,106,107,107,108,109,109,110,110,111,111,112,113,113,114,114,115,115,116,116,117,117,118,118,119,119,119,120,120,121,121,122,122,122,123,123,124,124,124,125,125,125,126,126,126,127,127,127,128,128,128,129,129,129,129,130,130,130,131,131,131,131,132,132,132,132,133,133,133,133,134,134,134,134,134,135,135,135,135,135,136,136,136,136,136,136,137,137,137,137,137,137,138,138,138,138,138,138,139,139,139,139,139,139,139,140,140,140,140,140,140,140,140,141,141,141,141,141,141,141,142,142,142,142,142,142,142,142,142,142,142,142,142,142,142,142,142,142] 

Answer 1

我能找到解決方案。您可以使用GPUImageToneCurveFilter作爲參考，並將RGB值數組作爲紋理傳遞。

Answer 2

glActiveTexture(GL_TEXTURE0);

這激活了第一採樣器，並且一旦被激活綁定東西出來，和取樣均勻設置爲0，指示採樣器的映射texgture單元。

你可能想要用glActiveTexture（GL_TEXTURE1），將uniform設置爲1等等，這樣你就可以在綁定表中設置所有其他採樣器和紋理條目。