[英]Texture Coordinates OSG GLSL
我有一張500x500像素的圖像,將其轉換為Texture2D到GLSL,然后將原始數據返回到C ++ / OSG。 我遇到了紋理坐標問題(GLSL上的坐標從0變為1)。 有人可以幫我嗎?
C ++代碼:
cv::Mat test = cv::Mat::zeros(512, 512, CV_8UC3);
test(cv::Rect( 0, 0, 255, 255)).setTo(cv::Scalar(255,0,0));
test(cv::Rect(256, 0, 255, 255)).setTo(cv::Scalar(0,255,0));
test(cv::Rect( 0, 256, 255, 255)).setTo(cv::Scalar(0,0,255));
test(cv::Rect(256, 256, 255, 255)).setTo(cv::Scalar(255,255,255));
osg::ref_ptr<osg::Image> image = new osg::Image;
image->setImage(512, 512, 3, GL_RGB, GL_BGR, GL_UNSIGNED_BYTE, test.data, osg::Image::NO_DELETE, 1);
osg::ref_ptr<osg::Texture2D> texture = new osg::Texture2D;
texture->setTextureSize(512, 512);
texture->setImage(image);
// Pass the texture to GLSL as uniform
osg::StateSet* ss = scene->getOrCreateStateSet();
osg::Uniform* samUniform = new osg::Uniform(osg::Uniform::SAMPLER_2D, "vertexMap");
samUniform->set(0);
ss->addUniform(samUniform);
ss->setTextureAttributeAndModes(0, texture, osg::StateAttribute::ON);
頂點代碼:
#version 130
void main() {
gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;
gl_TexCoord[0] = gl_TextureMatrix[0] * gl_MultiTexCoord0;
}
片段代碼:
#version 130
uniform sampler2D vertexMap;
out vec4 out_data;
void main() {
vec3 value = texture2D(vertexMap, gl_TexCoord[0].st).xyz;
out_data = vec4(value, 1);
}
這是我的輸入數據:
着色器的輸出數據:
我通過在片段着色器texture2D
texelFetch
替換為texture2D
來解決。 這兩個函數之間的區別可以在這里找到: https : //gamedev.stackexchange.com/questions/66448/how-do-opengls-texelfetch-and-texture-differ
#version 130
uniform sampler2D vertexMap;
out vec4 out_data;
void main() {
vec3 value = texelFetch(vertexMap, ivec2(gl_FragCoord.xy), 0).xyz;
out_data = vec4(value, 1);
}
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