I'm using glReadPixels to get depth value of select pixel, but i always get 1, how can i solve it? here is the code:
glEnable(GL_DEPTH_TEST);
..
glReadPixels(x, viewport[3] - y, 1, 1, GL_DEPTH_COMPONENT, GL_FLOAT, z);
Do I miss anything? And my rendering part is shown below. I use different shaders to draw different part of scene, so how should i make it correct to read depth value from buffer?
void onDisplay(void)
{
// Clear the window and the depth buffer
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// calculate the view matrix.
GLFrame eyeFrame;
eyeFrame.MoveUp(gb_eye_height);
eyeFrame.RotateWorld(gb_eye_theta * 3.1415926 / 180.0, 1.0, 0.0, 0.0);
eyeFrame.RotateWorld(gb_eye_phi * 3.1415926 / 180.0, 0.0, 1.0, 0.0);
eyeFrame.MoveForward(-gb_eye_radius);
eyeFrame.GetCameraMatrix(gb_hit_modelview);
gb_modelViewMatrix.PushMatrix(gb_hit_modelview);
// draw coordinate system
if(gb_bCoord)
{
DrawCoordinateAxis();
}
if(gb_bTexture)
{
GLfloat vEyeLight[] = { -100.0f, 100.0f, 150.0f };
GLfloat vAmbientColor[] = { 0.2f, 0.2f, 0.2f, 1.0f };
GLfloat vDiffuseColor[] = { 1.0f, 1.0f, 1.0f, 1.0f};
glUseProgram(normalMapShader);
glUniform4fv(locAmbient, 1, vAmbientColor);
glUniform4fv(locDiffuse, 1, vDiffuseColor);
glUniform3fv(locLight, 1, vEyeLight);
glUniform1i(locColorMap, 0);
glUniform1i(locNormalMap, 1);
gb_treeskl.Display(SetGeneralColor, SetSelectedColor, 0);
}
else
{
if(!gb_bOnlyVoxel)
{
if(gb_bPoints)
{
//GLfloat vPointColor[] = { 1.0, 1.0, 0.0, 0.6 };
GLfloat vPointColor[] = { 0.2, 0.0, 0.0, 0.9 };
gb_shaderManager.UseStockShader(GLT_SHADER_FLAT, gb_transformPipeline.GetModelViewProjectionMatrix(), vPointColor);
gb_treeskl.Display(NULL, NULL, 1);
}
if(gb_bSkeleton)
{
GLfloat vEyeLight[] = { -100.0f, 100.0f, 150.0f };
glUseProgram(adsPhongShader);
glUniform3fv(locLight, 1, vEyeLight);
gb_treeskl.Display(SetGeneralColor, SetSelectedColor, 0);
}
}
if(gb_bVoxel)
{
GLfloat vEyeLight[] = { -100.0f, 100.0f, 150.0f };
glUseProgram(adsPhongShader);
glUniform3fv(locLight, 1, vEyeLight);
SetVoxelColor();
glPolygonMode(GL_FRONT, GL_LINE);
glLineWidth(1.0f);
gb_treeskl.DisplayVoxel();
glPolygonMode(GL_FRONT, GL_FILL);
}
}
//glUniformMatrix4fv(locMVP, 1, GL_FALSE, gb_transformPipeline.GetModelViewProjectionMatrix());
//glUniformMatrix4fv(locMV, 1, GL_FALSE, gb_transformPipeline.GetModelViewMatrix());
//glUniformMatrix3fv(locNM, 1, GL_FALSE, gb_transformPipeline.GetNormalMatrix());
//gb_sphereBatch.Draw();
gb_modelViewMatrix.PopMatrix();
glutSwapBuffers();
}