I am trying to implement shadow mapping in my project for almost a week, and none of methods seem to work. The depth map texture seem to be empty.
I have been digging the whole internet and nothing helped me. Maybe I'm missing something in my code.
Here I start by creating the FBO and a Depth Map texture :
// create depthMap
int[] depthMapPtr = new int[1];
GLES30.glGenTextures(1, depthMapPtr, 0);
depthMap = depthMapPtr[0];
// use depthMap
GLES30.glBindTexture(GLES30.GL_TEXTURE_2D, depthMap);
GLES30.glTexImage2D(GLES30.GL_TEXTURE_2D, 0, GLES30.GL_DEPTH_COMPONENT16, size, size,
0, GLES30.GL_DEPTH_COMPONENT, GLES30.GL_UNSIGNED_SHORT, null);
GLES30.glTexParameteri(GLES30.GL_TEXTURE_2D, GLES30.GL_TEXTURE_MIN_FILTER, GLES30.GL_LINEAR);
GLES30.glTexParameteri(GLES30.GL_TEXTURE_2D, GLES30.GL_TEXTURE_MAG_FILTER, GLES30.GL_LINEAR);
GLES30.glTexParameteri(GLES30.GL_TEXTURE_2D, GLES30.GL_TEXTURE_WRAP_S, GLES30.GL_REPEAT);
GLES30.glTexParameteri(GLES30.GL_TEXTURE_2D, GLES30.GL_TEXTURE_WRAP_T, GLES30.GL_REPEAT);
// create fbo
int[] fboPtr = new int[1];
GLES30.glGenFramebuffers(1, fboPtr, 0);
fbo = fboPtr[0];
// use fbo
GLES30.glBindFramebuffer(GLES30.GL_FRAMEBUFFER, fbo);
GLES30.glFramebufferTexture2D(GLES30.GL_FRAMEBUFFER,
GLES30.GL_DEPTH_ATTACHMENT, GLES30.GL_TEXTURE_2D, depthMap, 0);
// draw/read buffers
int[] buffer = {GLES30.GL_NONE};
GLES30.glDrawBuffers(1, buffer, 0);
GLES30.glReadBuffer(GLES30.GL_NONE);
Then I define the depth shaders to render my scene on :
VERTEX SHADER FOR DEPTH :
#version 300 es
layout (location = 0) in vec3 vPos;
uniform mat4 mLightSpace;
uniform mat4 mModel;
void main()
{
gl_Position = mLightSpace * mModel * vec4(vPos, 1.0);
}
FRAGMENT SHADER FOR DEPTH :
#version 300 es
//out float fragDepth;
void main()
{
//fragDepth = gl_FragCoord.z;
}
(the comments change nothing, the result is the same).
Before rendering the scene from the shadow perspective, I use this piece of code to change the viewPort, clear depth buffer, bind the FBO :
GLES30.glBindTexture(GLES30.GL_TEXTURE_2D, 0);
// clear the depth
GLES30.glClear(GLES30.GL_DEPTH_BUFFER_BIT);
GLES30.glViewport(0, 0, size, size);
GLES30.glBindFramebuffer(GLES30.GL_FRAMEBUFFER, fbo);
// use the shader program for the shadows
useProgramShadow();
After I finish rendering the depth, I prepare everything to render the scene the usual way :
GLES30.glBindFramebuffer(GLES30.GL_FRAMEBUFFER, 0);
GLES30.glViewport(0, 0, GLWindow.width, GLWindow.height);
GLES30.glClear(GLES30.GL_COLOR_BUFFER_BIT | GLES30.GL_DEPTH_BUFFER_BIT);
GLES30.glActiveTexture(GLES30.GL_TEXTURE0);
GLES30.glBindTexture(GLES30.GL_TEXTURE_2D, depthMap);
useProgram();
Than I pass all the uniforms + the View/Projection matrix from the light perspective, and I render the scene.
I find the fragment position from the light perspective in the vertex shader with those lines :
const mat4 tMat = mat4(
0.5, 0.0, 0.0, 0.0,
0.0, 0.5, 0.0, 0.0,
0.0, 0.0, 0.5, 0.0,
0.5, 0.5, 0.5, 1.0
);
/* ... */
vFragPosLight = tMat * mLightSpace * mModel * vec4(vPosition, 1.0);
To then get the vFragPosLight
and the depthMap
texture
in vec4 vFragPosLight;
uniform sampler2DShadow depthMap;
...in the fragment shader and calculate the shadow with this line :
textureProj(depthMap, vFragPosLight);
...which always returns 0!
There is no errors with the shader compilations, no texture to framebuffer binding error, everything seems to be working find, but the depthMap is empty.
I really appreciate you for your help and thank you for taking your time to read!
I still don't know what the exact problem was, but I've read and used the Shadow Mapping part in this book about OpenGL ES 3.0 which worked.
It's possible that I had to disable all the color rendering components with glColorMask set to False.