使用 OpenGL/GLSL 1.2 更改纹理色调

Change tone of texture with OpenGL/GLSL 1.2

本文关键字：纹理 色调 OpenGL GLSL 使用      更新时间：2023-10-16

我想要图片的纹理改变色调。我有以下代码：

//Function main
  ...
  GLuint idvert = glGetAttribLocation(prog,"posicion");
  GLuint idcol  = glGetAttribLocation(prog,"color");
  GLuint idtex1 = glGetAttribLocation(prog,"coordtx1");
  GLuint px     = glGetAttribLocation(prog,"px");
  GLuint unit1  = glGetUniformLocation(prog,"tex1");
  ...
float ctex[] = {1.0,0.0,
              0.0,1.0,
              1.0,1.0,
              0.0,0.0};
float data[] = {1.0, 1.0,-5.0,
             -1.0,-1.0,-5.0,
              1.0,-1.0,-5.0,
             -1.0, 1.0,-5.0};
GLuint ind[] = {0,1,2,0,3,1};
GLfloat col[] = {1.0,0.0,0.0,1.0};

glGenBuffers(1,&triangleVBO);
glBindBuffer(GL_ARRAY_BUFFER,triangleVBO);
glBufferData(GL_ARRAY_BUFFER,sizeof(data),data,GL_STATIC_DRAW);
glGenBuffers(1,&triangleIND);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,triangleIND);
glBufferData(GL_ELEMENT_ARRAY_BUFFER,sizeof(ind),ind,GL_STATIC_DRAW);
glGenBuffers(1,&triangleCOL);
glBindBuffer(GL_ARRAY_BUFFER,triangleCOL);
glBufferData(GL_ARRAY_BUFFER,sizeof(col),col,GL_STATIC_DRAW);
glGenBuffers(1,&triangleT[0]);
glBindBuffer(GL_ARRAY_BUFFER,triangleT[0]);
glBufferData(GL_ARRAY_BUFFER,sizeof(ctex),ctex,GL_STATIC_DRAW);
//main loop
  glUseProgram(prog);
  glVertexAttrib1f(px,posicion);
  glVertexAttrib1fv(idcol,col);
  glActiveTexture(GL_TEXTURE0);
  glUniform1i(unit1,0);
  glBindTexture(GL_TEXTURE_2D,idtextura[0]);
  glEnableVertexAttribArray(idtex1);
  glEnableVertexAttribArray(idcol);
  glEnableVertexAttribArray(idvert);
  glBindBuffer(GL_ARRAY_BUFFER,triangleT[0]);
  glVertexAttribPointer(idtex1,2,GL_FLOAT,GL_FALSE,0,(void*)0);
  glBindBuffer(GL_ARRAY_BUFFER,triangleCOL);
  glVertexAttribPointer(idcol,4,GL_FLOAT,GL_FALSE,0,(void*)0);
  glBindBuffer(GL_ARRAY_BUFFER,triangleVBO);
  glVertexAttribPointer(idvert,3,GL_FLOAT,GL_FALSE,0,(void*)0);
  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,triangleIND);
  glDrawElements(GL_TRIANGLES,6,GL_UNSIGNED_INT,(void*)0);
  glBindTexture(GL_TEXTURE_2D,0);
  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,0);
  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,0);
  glDisableVertexAttribArray(idvert);
  glDisableVertexAttribArray(idcol);
  glDisableVertexAttribArray(idtex1);
  glUseProgram(0);

这些是我的着色器：

//Vertex shader
#version 120
attribute vec4 posicion;
attribute vec4 color;
attribute vec2 coordtx1;
attribute float px;
varying vec2 UV1;
varying vec4 colfrag;
vec4 tmp;
void main(){
  tmp = vec4(posicion.x + px,posicion.y,posicion.z,1.0);
  gl_Position = gl_ModelViewProjectionMatrix * tmp;  
  colfrag = color;
  UV1 = coordtx1;
} 
//Fragment Shader
#version 120
uniform sampler2D tex1;
varying vec2 UV1;
varying vec4 colfrag;
void main(){
  vec4 color1 = texture2D(tex1,UV1);
  gl_FragColor = color1 * colfrag;
}

问题是当我渲染时，我的图像是完全黑色的......怎么了？

对应于 tex1 的图像数据似乎没有加载到任何地方 - 您错过了对 glTexImage2D 的调用，可以在其中加载此数据。如果在绘制调用后检查glGetError，则可能会看到错误。

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