#import "GPUImageMaskFilter.h"
|
|
#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
|
NSString *const kGPUImageMaskShaderString = SHADER_STRING
|
(
|
varying highp vec2 textureCoordinate;
|
varying highp vec2 textureCoordinate2;
|
|
uniform sampler2D inputImageTexture;
|
uniform sampler2D inputImageTexture2;
|
|
void main()
|
{
|
lowp vec4 textureColor = texture2D(inputImageTexture, textureCoordinate);
|
lowp vec4 textureColor2 = texture2D(inputImageTexture2, textureCoordinate2);
|
|
//Averages mask's the RGB values, and scales that value by the mask's alpha
|
//
|
//The dot product should take fewer cycles than doing an average normally
|
//
|
//Typical/ideal case, R,G, and B will be the same, and Alpha will be 1.0
|
lowp float newAlpha = dot(textureColor2.rgb, vec3(.33333334, .33333334, .33333334)) * textureColor2.a;
|
|
gl_FragColor = vec4(textureColor.xyz, newAlpha);
|
// gl_FragColor = vec4(textureColor2);
|
}
|
);
|
#else
|
NSString *const kGPUImageMaskShaderString = SHADER_STRING
|
(
|
varying vec2 textureCoordinate;
|
varying vec2 textureCoordinate2;
|
|
uniform sampler2D inputImageTexture;
|
uniform sampler2D inputImageTexture2;
|
|
void main()
|
{
|
vec4 textureColor = texture2D(inputImageTexture, textureCoordinate);
|
vec4 textureColor2 = texture2D(inputImageTexture2, textureCoordinate2);
|
|
//Averages mask's the RGB values, and scales that value by the mask's alpha
|
//
|
//The dot product should take fewer cycles than doing an average normally
|
//
|
//Typical/ideal case, R,G, and B will be the same, and Alpha will be 1.0
|
float newAlpha = dot(textureColor2.rgb, vec3(.33333334, .33333334, .33333334)) * textureColor2.a;
|
|
gl_FragColor = vec4(textureColor.xyz, newAlpha);
|
// gl_FragColor = vec4(textureColor2);
|
}
|
);
|
#endif
|
|
@implementation GPUImageMaskFilter
|
|
- (id)init;
|
{
|
if (!(self = [super initWithFragmentShaderFromString:kGPUImageMaskShaderString]))
|
{
|
return nil;
|
}
|
|
return self;
|
}
|
|
- (void)renderToTextureWithVertices:(const GLfloat *)vertices textureCoordinates:(const GLfloat *)textureCoordinates;
|
{
|
glEnable(GL_BLEND);
|
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
|
[super renderToTextureWithVertices:vertices textureCoordinates:textureCoordinates];
|
glDisable(GL_BLEND);
|
}
|
|
@end
|