2纹理,1个着色器 - OpenGL ES 2.0

Question

ES 2.0新手在这里.我目前正在尝试使用ES 2.0和PowerVR SDK从立体图像制作一些3D隔行扫描图像.我可以输出一个图像纹理很好,但当我尝试输出第二个时,我似乎覆盖了第一个.所以,我的问题是,鉴于下面的片段着色器,我可以用它来绘制两个纹理,或者sampler2d均匀只能绑定到一个纹理单元吗？这是片段着色器(取自PowerVR"培训课程"示例程序):

    uniform sampler2D sampler2d;\
    varying mediump vec2    myTexCoord;\
    void main (void)\
    {\
        gl_FragColor = texture2D(sampler2d,myTexCoord);\
    }";

这是我如何将图像纹理加载到着色器中:

//LEFT IMAGE
glActiveTexture(GL_TEXTURE0);
glGenTextures(1, &m_uiTexture_left);                                    
glBindTexture(GL_TEXTURE_2D, m_uiTexture_left);
glUniform1i(glGetUniformLocation(m_uiProgramObject, "sampler2d"), 0);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, pwr2Width, pwr2Height,0, GL_RGB, GL_UNSIGNED_BYTE, xImageL); 
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
GLfloat afVertices[30] = {0.0};
genVertices(afVertices);
glGenBuffers(1, &m_ui32Vbo_leftimage);                                  
m_ui32VertexStride = 5 * sizeof(GLfloat); // 3 floats for the pos, 2 for the UVs
glBindBuffer(GL_ARRAY_BUFFER, m_ui32Vbo_leftimage);
glBufferData(GL_ARRAY_BUFFER, 6 * m_ui32VertexStride, afVertices, GL_STATIC_DRAW);  
glBindBuffer(GL_ARRAY_BUFFER, 0);

//RIGHT IMAGE
glActiveTexture(GL_TEXTURE1);
glGenTextures(1, &m_uiTexture_right);                                   
glBindTexture(GL_TEXTURE_2D, m_uiTexture_right);
glUniform1i(glGetUniformLocation(m_uiProgramObject, "sampler2d"), 1);   
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, pwr2Width, pwr2Height,0, GL_RGB, GL_UNSIGNED_BYTE, xImageR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glGenBuffers(1, &m_ui32Vbo_rightimage);                     
m_ui32VertexStride = 5 * sizeof(GLfloat); // 3 floats for the pos, 2 for the UVs
glBindBuffer(GL_ARRAY_BUFFER, m_ui32Vbo_rightimage);
glBufferData(GL_ARRAY_BUFFER, 6 * m_ui32VertexStride, afVertices, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);

那么,这段代码只是覆盖了sampler2d统一吗？我需要另一个制服或着色器用于第二张图像吗？

Answer 1

好的,正如我在上面的评论中提到的,我最终在这里找到了答案:http://www.opentk.com/node/2559.正如该论坛上的用户"Profet"所提到的,重新使用片段着色器的一种方法是将glUniform1i()调用向下移动到渲染函数,即调用glUniform1i()将第一个纹理传递给着色器,调用glDraw(绘制纹理),然后调用glUniform1i()并将第二个纹理传递给着色器(并绘制).所以现在我的initialise()代码如下:

//LEFT IMAGE
glActiveTexture(GL_TEXTURE0);
glGenTextures(1, &m_uiTexture_left);                                    
glBindTexture(GL_TEXTURE_2D, m_uiTexture_left);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, pwr2Width, pwr2Height,0, GL_RGB, GL_UNSIGNED_BYTE, xImageL); 
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
GLfloat afVertices[30] = {0.0};
genVertices(afVertices);
glGenBuffers(1, &m_ui32Vbo_leftimage);                                  
m_ui32VertexStride = 5 * sizeof(GLfloat); // 3 floats for the pos, 2 for the UVs
glBindBuffer(GL_ARRAY_BUFFER, m_ui32Vbo_leftimage);
glBufferData(GL_ARRAY_BUFFER, 6 * m_ui32VertexStride, afVertices, GL_STATIC_DRAW);  
glBindBuffer(GL_ARRAY_BUFFER, 0);

//RIGHT IMAGE
glActiveTexture(GL_TEXTURE1);
glGenTextures(1, &m_uiTexture_right);                                   
glBindTexture(GL_TEXTURE_2D, m_uiTexture_right);   
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, pwr2Width, pwr2Height,0, GL_RGB, GL_UNSIGNED_BYTE, xImageR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glGenBuffers(1, &m_ui32Vbo_rightimage);                     
m_ui32VertexStride = 5 * sizeof(GLfloat); // 3 floats for the pos, 2 for the UVs
glBindBuffer(GL_ARRAY_BUFFER, m_ui32Vbo_rightimage);
glBufferData(GL_ARRAY_BUFFER, 6 * m_ui32VertexStride, afVertices, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);

我的render()代码如下:

//&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&  LEFT IMAGE &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
glEnable(GL_STENCIL_TEST);
glStencilFunc(GL_NOTEQUAL, 1, 1); //draw on uneven lines only
glUniform1i(glGetUniformLocation(m_uiProgramObject, "sampler2d"), 0); //pass texture unit 0 to shader
glBindBuffer(GL_ARRAY_BUFFER, m_ui32Vbo_leftimage);     // unbound this near the end of initView, so need to re-bind it
glEnableVertexAttribArray(VERTEX_ARRAY);
glVertexAttribPointer(VERTEX_ARRAY, 3, GL_FLOAT, GL_FALSE, m_ui32VertexStride, 0);
glEnableVertexAttribArray(TEXCOORD_ARRAY);
glVertexAttribPointer(TEXCOORD_ARRAY, 2, GL_FLOAT, GL_FALSE, m_ui32VertexStride, (void*) (3 * sizeof(GLfloat)));
glDrawArrays(GL_TRIANGLES, 0, 6);
glBindBuffer(GL_ARRAY_BUFFER, 0);
//&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&  RIGHT IMAGE  &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
glEnable(GL_STENCIL_TEST);
glStencilFunc(GL_EQUAL, 1, 1);  //draw on even lines only
glUniform1i(glGetUniformLocation(m_uiProgramObject, "sampler2d"), 1);
glBindBuffer(GL_ARRAY_BUFFER, m_ui32Vbo_rightimage);
glEnableVertexAttribArray(VERTEX_ARRAY);
glVertexAttribPointer(VERTEX_ARRAY, 3, GL_FLOAT, GL_FALSE, m_ui32VertexStride, 0);
glEnableVertexAttribArray(TEXCOORD_ARRAY);
glVertexAttribPointer(TEXCOORD_ARRAY, 2, GL_FLOAT, GL_FALSE, m_ui32VertexStride, (void*) (3 * sizeof(GLfloat)));
glDrawArrays(GL_TRIANGLES, 0, 6);
glBindBuffer(GL_ARRAY_BUFFER, 0);

希望有一天这会帮助别人!:)