No alpha blending working for me in OpenGL 4.6 - opengl

I am working on a particle system using OpenGL and version 460 shaders that are compiled to SPIR-V.
My particles are based on PNG textures with alpha and it's actually pretty straight forward, I have done it on earlier OpenGL versions before.
However, the particle in the output window remains to be a square, the corners are black - meaning, the alpha channel is drawn as black. I used different PNG files, one with the particle as grey on alpha or grey on black. I set in the fragment shader the forth component to 0.0 or 0.5 to see any change, but nothing changed. I tried to change the formats in the loadTexture function, but still the same.
I tried all different kinds of blending modes and changed the order of the lines. I noticed in RenderDoc, that the target blend is disabled. But no change of glEnable(GL_BLEND) to another position was helpful.
I would really appreciate your help!
// init stuff
glEnable(GL_POINT_SPRITE);
initbasicShaders(); // vertex, fragment
initTexture();
...
void application::initTexture()
{
m_ParticleTex = Texture(); // empty constructor
m_ParticleTex.loadTexture(TEXTURE_PATH);
GLint baseImageLoc = glGetUniformLocation(m_RenderProgramHandle, "u_Texture");
glUseProgram(m_RenderProgramHandle);
glUniform1i(baseImageLoc, 0);
glActiveTexture(GL_TEXTURE0 + 0);
glBindTexture(GL_TEXTURE_2D, m_ParticleTex.getTextureID());
}
// using the library stb_image
void Texture::loadTexture(const char* fileName)
{
int channels, width, height;
unsigned char * localBuffer;
m_FilePath = fileName;
localBuffer = stbi_load(fileName, &width, &height, &channels, 4);
glGenTextures(1, &m_TextureID);
glBindTexture(GL_TEXTURE_2D, m_TextureID);
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, localBuffer);
glBindTexture(GL_TEXTURE_2D, 0);
if (localBuffer) {
stbi_image_free(localBuffer);
}
}
...
...
...
// Now - the render loop:
void application::runOpenGLBuffer()
{
Log::logInfoRun(m_Name, "OpenGL buffer");
glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_BLEND);
glEnable(GL_POINT_SMOOTH);
glDisable(GL_DEPTH_TEST);
glEnable(GL_ALPHA_TEST);
glPointSize(PARTICLE_SIZE);
glHint(GL_POINT_SMOOTH_HINT, GL_NICEST);
glUseProgram(m_RenderProgramHandle);
this->updateTextures();
glDrawArrays(GL_POINTS, 0, NUM_PARTICLES);
}
...
// and the fragment shader
#version 460
#extension GL_ARB_separate_shader_objects : enable
layout(std430, binding = 3) buffer density_block
{
float density[];
};
void main()
{
// densitColor is just a variable color from density
vec4 particleColor = vec4(texture(u_Texture, gl_PointCoord) * densityColor);
color = particleColor;
}
And here the output in the render frame and information from RenderDoc:

The parameter to glEnable (like GL_BLEND or GL_POINT_SMOOTH) is a enumerator constant rather than a bits of a bit field. Different enumerator constants can't be concatenated by the | operator. Each state has to be enabled separately:
glEnable(GL_BLEND | GL_POINT_SMOOTH);
glEnable(GL_BLEND);
glEnable(GL_POINT_SMOOTH);
Note, the bitwise or operation calculates a new value by performing "or" to each bit of both values. The result may have not any meaning to glEnable. This causes that neither GL_BLEND nor GL_POINT_SMOOTH is enabled in your code.

Related

GLSL shader not writing to color_attatchment1

I am trying to render to multiple render targets, I set up a float texture and bound it to COLOR_ATTACHMENT1. This all works well and the buffer is created and bound properly. The buffer is even drawn to if I let all the shaders draw to it (glDrawBuffers(..)) instead of just the shader I have set up to draw to it (layout (location = 1) out ..). The issue is the shader that should be altering the values doesn't. I know this using Nsight graphics to preview COLOR_ATTATCHMENT1:
(note the white pixels on the left are a border from nsight)
As we can see, the buffer has two writes but neither change the buffer at all. The glClear shouldn't change anything here (I think) because glDrawBuffers doesn't contain this buffer yet.
This is what COLOR_ATTATCHMENT1 looks like if I let every shader write to it (glDrawBuffers(..) //with both attatchments):
These shaders don't write to this attatchment at all (layout (location = 0) no location 1) and work perfectly, but again, the one shader that does write to it doesn't. The crates should be writing white pixels, they can be seen here:
(note: this screenshot has post processing applied)
I don't know it's not writing but every other shader has no problem. The framebuffer is set up properly:
The texture is set up with a format of GL_RGB32F because I want this to be a float texture with the viewspace normals, but the problem persists if I use GL_RGB or RGBA. The framebuffer is multisampled and all the textures are multisampled. This is the creation code (ommited glGen.....):
glBindFramebuffer(GL_FRAMEBUFFER, fboMultisample);
glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, colourTexMs); //..
glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, sampleLevel, GL_RGB, windowWidth, windowHeight, GL_FALSE); //..
glTexParameteri(GL_TEXTURE_2D_MULTISAMPLE, GL_TEXTURE_MIN_FILTER, GL_LINEAR); //..
glTexParameteri(GL_TEXTURE_2D_MULTISAMPLE, GL_TEXTURE_MAG_FILTER, GL_LINEAR); //.. magnified ..
glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, depthTexMs);
glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, sampleLevel, GL_DEPTH_COMPONENT32, windowWidth, windowHeight, GL_FALSE); //..
glTexParameteri(GL_TEXTURE_2D_MULTISAMPLE, GL_TEXTURE_MIN_FILTER, GL_LINEAR); //..
glTexParameteri(GL_TEXTURE_2D_MULTISAMPLE, GL_TEXTURE_MAG_FILTER, GL_LINEAR); //..
glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, normalTexMs);
glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, sampleLevel, GL_RGB32F, windowWidth, windowHeight, GL_FALSE); //..
glTexParameteri(GL_TEXTURE_2D_MULTISAMPLE, GL_TEXTURE_MIN_FILTER, GL_LINEAR); //..
glTexParameteri(GL_TEXTURE_2D_MULTISAMPLE, GL_TEXTURE_MAG_FILTER, GL_LINEAR); //..
And this is the attachment code (fboMultisampled is still bound to GL_FRAMEBUFFER):
glBindTexture(GL_TEXTURE_2D, 0); //unbind textures for safety
glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, 0); //unbind textures for safety
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D_MULTISAMPLE, colourTexMs, 0); //attatch textures to the framebuffer
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D_MULTISAMPLE, depthTexMs, 0); //..
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_2D_MULTISAMPLE, normalTexMs, 0); //.. 0 = mipmap level
And this is the shader that should be writing to COLOR_ATTATCHMENT1 (result calculation is omitted):
layout (location = 0) out vec4 fragColor;
layout (location = 1) out vec3 viewNorm;
//..
void main()
{
//..
fragColor = vec4(result, 1.0f);
viewNorm = vec3(1.f);
}
So in short I don't understand why the shader isn't writing to COLOR_ATTATCHMENT1.
note: there aren't any OpenGL errors reported.
fixed it by outputting a vec4 in the shader even though the texture is rgb32F

OpenGL Depth Texture is the same as Color Texture

I'm trying to visualize the depth texture attached to a custom fbo in opengl. I expected to see a "foggy" looking, greyscale output - the problem is that the output seems like it's the same as the color texture - I mean it's the exact same color texture. Am I actually rendering the same thing into 2 different textures?
Creating the depth texture:
glGenTextures(1, &m_DepthTxId);
glBindTexture(GL_TEXTURE_2D, m_DepthTxId);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, width, height, 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_BYTE, (void*)nullptr);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
Creating the fbo & attaching the color/depth textures:
glGenFramebuffers(1, &m_Id);
glBindFramebuffer(GL_FRAMEBUFFER, m_Id);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_ColorTxId, 0);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, m_DepthTxId, 0);
m_DrawBuffers[0] = GL_COLOR_ATTACHMENT0;
glDrawBuffers(1, m_DrawBuffers);
The interesting thing is that without adding the depth texture, the objects are displayed in the order they were rendered (scene looks messed up) - but when I add the depth texture, everything looks fine as you would expect with depth testing.
But how come when I give the depth texture to the shader it just displays the color-texture? Am I rendering color data into my depth texture, or..?
Apologies, but I'm fairly new to working with fbos :P
Additional info:
Rendering the fbo-textures onto a quad:
glActiveTexture(GL_TEXTURE0); // Color
glBindTexture(GL_TEXTURE_2D, m_Fbo->getColorTxId()); // ColorTexture ID
glUniform1i(m_Shader->getColorSampler(), 0); // ColorSampler Location
glActiveTexture(GL_TEXTURE1); // Depth
glBindTexture(GL_TEXTURE_2D, m_Fbo->getDepthTxId()); // DepthTexture ID
glUniform1i(m_Shader->getDepthSampler(), 0); // DepthSampler Location
glBindVertexArray(m_Fbo->getVaoId());
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, (void*)0);
glBindVertexArray(0);
Getting the sampler locations from the shader:
m_Location_ColorTxSampler = glGetUniformLocation(m_ProgramId, "colorSampler");
m_Location_DepthTxSampler = glGetUniformLocation(m_ProgramId, "depthSampler");
Shader:
in vec2 uv;
uniform sampler2D colorSampler;
uniform sampler2D depthSampler;
out vec4 color;
void main()
{
color = vec4(texture2D(depthSampler, uv).rgb, 1.0);
}
To me the whole thing seems correct, unless the 2 samplers are at the same location.. I'm sure that's not possible
If you bind the depth texture to unit 1...
glActiveTexture(GL_TEXTURE1); // Depth
glBindTexture(GL_TEXTURE_2D, m_Fbo->getDepthTxId()); // DepthTexture ID
... you should not tell the shader to sample from unit 0:
glUniform1i(m_Shader->getDepthSampler(), 0); // DepthSampler Location

OpenGL - Unable to write to frame buffer (or read it properly)

So I've been trying to get shadow mapping to work, but I was unsuccessful, and I am now trying to simply write anything to the frame buffer and then render it to a quad as a texture. I've been looking at this small piece of code for 10 hours, so I thought it might finally be time to ask for some help. Do let me know if you need any more information or if something is unclear.
I started by following this tutorial. After completing it two times, and straight copy pasting a third time I gave up, and started to look elsewhere for information. My current code is a bit of a mess, but I have tried to extract what is crucial
Here is how I set up my FBO with a TEXTURE2D (_shadowMap and _shadowMapFBO are private variables in the class acting as the main program):
glGenTextures(1, &_shadowMap);
glBindTexture(GL_TEXTURE_2D, _shadowMap);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT32, SHADOW_WIDTH, SHADOW_HEIGHT, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL);
glGenFramebuffers(1, &_shadowMapFBO);
glBindFramebuffer(GL_FRAMEBUFFER, _shadowMapFBO);
glDrawBuffer(GL_NONE);
glReadBuffer(GL_NONE);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, _shadowMap, 0);
GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
{
std::cout << "Frame buffer failed" << std::endl;
system("pause");
exit(1);
}
glBindFramebuffer(GL_FRAMEBUFFER, 0);
I then do the first render pass in the main loop:
glViewport(0, 0, SHADOW_WIDTH, SHADOW_HEIGHT);
glBindFramebuffer(GL_FRAMEBUFFER, _shadowMapFBO);
glClear(GL_DEPTH_BUFFER_BIT);
_shadowShader.bind();
glBindVertexArray(_cubeVAO);
glDrawElements(GL_TRIANGLES, _numberOfIndicesCube, GL_UNSIGNED_SHORT, 0);
glBindVertexArray(_planeVAO);
glDrawElements(GL_TRIANGLES, _numberOfIndicesPlane, GL_UNSIGNED_SHORT, 0);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glDrawBuffer(GL_BACK);
glReadBuffer(GL_BACK);
Initially I wanted to create a shadow map, but at this point I'm simply trying to write an explicit value to the entire texture attached to the frame buffer using the following shader pair (the one used by _shadowShader)
Vertex
#version 450
in layout(location=0) vec3 position;
uniform mat4 mvp;
void main()
{
gl_Position = mvp * vec4(position, 1.0f);
}
Fragment
#version 450
out float depth;
void main()
{
depth = 0.0f;
}
I then finish up by trying to display the texture on a quad:
glViewport(0, 0, _screenWidth, _screenHeight);
glClearColor(0.7f, 0.5f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
_testShader.bind();
glBindTexture(GL_TEXTURE_2D, _shadowMap);
glBindVertexArray(_quadVAO);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, 0);
Here is the fragment shader for the quad:
#version 450
in vec2 textureCoordinates;
uniform sampler2D _shadowMap;
out vec4 color;
void main()
{
float depth = texture2D(_shadowMap, textureCoordinates).r;
color = texture2D(_shadowMap, textureCoordinates);
}
But to my continuous frustration, the quad appears white although I output 0.0f (black) from the fragment shader...I know the quad is able to display a texture, as I've been able to render a normal texture displaying a .jpg onto it. So, this is where I'm at now; any ideas, pointers, thoughts, motivational words etc?
EDIT I: So after some more time I have at least figured out that the texture is loaded correctly and that I'm able to read from it. I did this by actually loading a image onto it during initialization and then not writing to it. The quad then displays the texture correctly. So there must be something wrong with how I'm writing to it.
EDIT II: So I got it working; I sat down with a TA and copy pasted the code (yeah, I know...doesn't get much better than that) and it now works. Thanks Bart :)
Your shadow pass fragment shader is just wrong:
#version 450
out float depth;
void main()
{
depth = 0.0f;
}
This does just declare a single channel color output, which will be written to the color attachment (which you don't have). Since you want to write to the depth attachment of your FBO, you have to use the builtin gl_FragDepth output variable. If you don't do it, the GL will write the lineariliy interpolated window space depth value to the depth buffer.
Note that typically, you clear the depth buffer to 1.0, and when using a typical perspective projection, your objects would appear very close to 1.0, say at 0.99something, as the depth value, so it is very likely that converting the result to just 8 bit grayscale will look all white.

Shadow Mapping is faint

I am trying to do OpenGL GLSL based shadow mapping. The trouble is that after I have finished rendering the shadow map, I am rendering the map to the screen to test whether the rendering works correctly or not i.e I am simply using the newly generated texture as a texture which I am mapping on to the screen. The expected result is that I will see the new texture. But instead, what i am seeing is a white area with the texture drawn but extremely faint. That is, if I tilt the screen at a certain angle only then I can see the faint outlines of the shadow map.
Can anyone tell me if I am doing anything wrong?
Here is relevant parts of my code :
void Init_FBO()
{
//glActiveTexture(GL_TEXTURE3);
GLfloat border[] = {1.0f, 0.0f, 0.0f, 0.0f};
glGenTextures(1, &depthTex);
glBindTexture(GL_TEXTURE_2D, depthTex);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT24,900,900, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
glTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_BORDER_COLOR, border);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_REF_TO_TEXTURE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC, GL_LESS);
glBindTexture(GL_TEXTURE_2D,0);
glGenFramebuffers(1, &shadowFBO);
glBindFramebuffer(GL_FRAMEBUFFER, shadowFBO);
glDrawBuffer(GL_NONE);
glReadBuffer(GL_NONE);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, depthTex, 0);
glBindFramebuffer(GL_FRAMEBUFFER, 0); // go back to the default framebuffer
// check FBO status
GLenum FBOstatus = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER);
if(FBOstatus != GL_FRAMEBUFFER_COMPLETE)
{
printf("GL_FRAMEBUFFER_COMPLETE failed, CANNOT use FBO\n");
}
else
{
printf("Frame Buffer Done Succesfully\n");
}
}
void generateShadowTex()
{
//Calculate final ligting properties
glm::vec4 a_f=light_ambient*mat_ambient;
glm::vec4 d_f=light_diffuse*mat_diffuse;
glm::vec4 s_f=light_specular*mat_specular;
int counter=0;
glEnable(GL_DEPTH_TEST); // need depth test to correctly draw 3D objects
glClearColor(0,0,0,1);
//glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glClear(GL_DEPTH_BUFFER_BIT);
glCullFace(GL_FRONT);
if(wframe)
glPolygonMode(GL_FRONT_AND_BACK,GL_LINE);
else
glPolygonMode(GL_FRONT_AND_BACK,GL_FILL);
glUseProgram(programObject);
//Draw the stuff using Light Position as camera
//glutSwapBuffers();
glActiveTexture(GL_TEXTURE3);
glBindTexture(GL_TEXTURE_2D,depthTex);
glUseProgram(0);
}
void generateScene()
{
//Calculate final ligting properties
glm::vec4 a_f=light_ambient*mat_ambient;
glm::vec4 d_f=light_diffuse*mat_diffuse;
glm::vec4 s_f=light_specular*mat_specular;
int counter=0;
glEnable(GL_DEPTH_TEST); // need depth test to correctly draw 3D objects
glClearColor(0,0,0,1);
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
//Draw the stuff using camera as camera position
}
glutSwapBuffers();
glUseProgram(0);
}
void display()
{
glBindFramebuffer(GL_FRAMEBUFFER, shadowFBO);
generateShadowTex();
glBindFramebuffer(GL_FRAMEBUFFER, 0);
generateScene();
}
your depth texture is looking normally, depth covers range from near to far clip planes, you can set some reasonable clipping planes using glFrustumf(...)

Trailing shadows in Shadow Map

I have created the shadow map. However it has two problems :
1. The shadow comes into picture only when I change the model matrix. i.e initially there is no shadows, but when i press a key to move the figure, that is there is a change in the model matrix, the shadow appears.
2. There is a trail of old renders on the texture on the framebuffer that results in a long trail.
Can anyone shed any light on this?
THis is the screenshot of the problem
Edit Code here :
void generateShadowTex()
{
//Calculate final ligting properties
glm::vec4 a_f=light_ambient*mat_ambient;
glm::vec4 d_f=light_diffuse*mat_diffuse;
glm::vec4 s_f=light_specular*mat_specular;
int counter=0;
glClear(GL_DEPTH_BUFFER_BIT);
glEnable(GL_DEPTH_TEST); // need depth test to correctly draw 3D objects
glClearColor(0,0,0,1);
//glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
if(wframe)
glPolygonMode(GL_FRONT_AND_BACK,GL_LINE);
else
glPolygonMode(GL_FRONT_AND_BACK,GL_FILL);
glActiveTexture(GL_TEXTURE3);
glBindTexture(GL_TEXTURE_2D,depthTex);
// MAths here for mvp manupulation
//Draw Elements
if(a<17 || a==18)
glDrawElements(GL_QUADS, masterNumberIndices[a], GL_UNSIGNED_INT, (char*) NULL+0);
else
glDrawElements(GL_TRIANGLES, masterNumberIndices[a], GL_UNSIGNED_INT, (char*) NULL+0);
glBindVertexArrayAPPLE(0);
}
glUseProgram(0);
}
void Init_FBO()
{
GLfloat border[] = {1.0f, 0.0f, 0.0f, 0.0f};
//glActiveTexture(GL_TEXTURE3);
glGenTextures(1, &depthTex);
glBindTexture(GL_TEXTURE_2D, depthTex);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT24,900,900, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
glTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_BORDER_COLOR, border);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_REF_TO_TEXTURE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC, GL_LESS);
glBindTexture(GL_TEXTURE_2D,0);
glGenFramebuffers(1, &shadowFBO);
glBindFramebuffer(GL_FRAMEBUFFER, shadowFBO);
glDrawBuffer(GL_NONE);
glReadBuffer(GL_NONE);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, depthTex, 0);
glBindFramebuffer(GL_FRAMEBUFFER, 0); // go back to the default framebuffer
// check FBO status
GLenum FBOstatus = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER);
if(FBOstatus != GL_FRAMEBUFFER_COMPLETE)
{
printf("GL_FRAMEBUFFER_COMPLETE failed, CANNOT use FBO\n");
}
else
{
printf("Frame Buffer Done Succesfully\n");
}
}
void display()
{
glBindFramebuffer(GL_FRAMEBUFFER, shadowFBO);
generateShadowTex();
glBindFramebuffer(GL_FRAMEBUFFER, 0);
generateScene();
}
You need to enable the depth buffer before you clear it. From the OpenGL specification:
If a buffer is not present, then a glClear directed at that buffer has no effect. 1
And:
GL_DEPTH_TEST
If enabled, do depth comparisons and update the depth buffer. Note that even if the depth buffer exists and the depth mask is non-zero, the depth buffer is not updated if the depth test is disabled. 2
As to the first part of your question, I can only guess what the problem might be, but you're probably not initializing the model matrix correctly.