我試圖用GLSL着色器將YUV(YV12)轉換爲RGB。關於使用GLSL將YUV(YV12)轉換爲RGB
如下圖所示。
- 讀取圖像文件原始YUV(YV12)數據
- 濾波Y,Cb和Cr從原始YUV(YV12)數據
- 映射紋理
- 發送片段着色器。
但結果圖像與原始數據不一樣。
下面的圖像是原始數據。
screenshot of raw image link(Available for download)
和下方圖像是轉換數據。
screenshot of convert image link(Available for download)
以下是我的源代碼。
- (void) readYUVFile
{
...
NSData* fileData = [NSData dataWithContentsOfFile:file];
NSInteger width = 720;
NSInteger height = 480;
NSInteger uv_width = width/2;
NSInteger uv_height = height/2;
NSInteger dataSize = [fileData length];
GLint nYsize = width * height;
GLint nUVsize = uv_width * uv_height;
GLint nCbOffSet = nYsize;
GLint nCrOffSet = nCbOffSet + nUVsize;
Byte* uData = spriteData + nCbOffSet;
Byte* vData = uData + nUVsize;
GLfloat imageY[ 345600 ], imageU[ 86400 ], imageV[ 86400 ];
int x, y, nIndexY = 0, nIndexUV = 0;
for(y = 0; y < height; y++)
{
for(x = 0; x < width; x++)
{
imageY[ nIndexY ] = (GLfloat)spriteData[ nIndexY ] - 16.0;
if((y < uv_height) && (x < uv_width))
{
imageU[ nIndexUV ] = (GLfloat)uData[ nIndexUV ] - 128.0;
imageV[ nIndexUV ] = (GLfloat)vData[ nIndexUV ] - 128.0;
nIndexUV++;
}
nIndexY++;
}
}
m_YpixelTexture = [self textureY:imageY widthType:width heightType:height];
m_UpixelTexture = [self textureU:imageU widthType:uv_width heightType:uv_height];
m_VpixelTexture = [self textureV:imageV widthType:uv_width heightType:uv_height];
...
}
- (GLuint) textureY: (GLfloat*)imageData
widthType: (int) width
heightType: (int) height
{
GLuint texName;
glActiveTexture(GL_TEXTURE0);
glGenTextures(1, &texName);
glBindTexture(GL_TEXTURE_2D, texName);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageData);
return texName;
}
- (GLuint) textureU: (GLfloat*)imageData
widthType: (int) width
heightType: (int) height
{
GLuint texName;
glActiveTexture(GL_TEXTURE1);
glGenTextures(1, &texName);
glBindTexture(GL_TEXTURE_2D, texName);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageData);
return texName;
}
- (GLuint) textureV: (GLfloat*)imageData
widthType: (int) width
heightType: (int) height
{
GLuint texName;
glActiveTexture(GL_TEXTURE2);
glGenTextures(1, &texName);
glBindTexture(GL_TEXTURE_2D, texName);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageData);
return texName;
}
以下是Fragment Shader的源代碼。
uniform sampler2D Ytexture; // Y Texture Sampler
uniform sampler2D Utexture; // U Texture Sampler
uniform sampler2D Vtexture; // V Texture Sampler
varying highp vec2 TexCoordOut;
void main()
{
highp float y, u, v;
highp float r, g, b;
y = texture2D(Ytexture, TexCoordOut).p;
u = texture2D(Utexture, TexCoordOut).p;
v = texture2D(Vtexture, TexCoordOut).p;
y = 1.1643 * (y - 0.0625);
u = u - 0.5;
v = v - 0.5;
r = y + 1.5958 * v;
g = y - 0.39173 * u - 0.81290 * v;
b = y + 2.017 * u;
gl_FragColor = highp vec4(r, g, b, 1.0);
}
Y數據是好的,但U和V數據是不好的。圖像數據的y軸是反向輸出。
如何解決此問題?
第二個截圖對我不起作用。有沒有重新提供它的機會? – Tommy 2012-02-01 01:32:02