Currently i'm rewriting my rendering to use defered shading in any case, for this i also rewrite the 3D shaders and i'm aiming for Physical based shading.
Now something strange happens, while it worked all the time before and is still working with all other shaders, the uniform variable is not working anymore like expected. If i assign 2 textures two the different texture slots it shows always only one of them.
Basically i'm calling the following to bind my texture:
glActiveTexture(slot); // slot is GL_TEXTURE0 = 0x84C0 + _TextureCount
glBindTexture(type, handle);
glUniform1i(uniform.Location, _TextureCount);
// Always passing, so the uniform is assigned to the right shader
Debug.Assert(_TextureCount == glGetUniformiv(_ShaderHandle, uniform.Location));
_TextureCount++;
No error is generated by OpenGL and all uniform locations are correct ( Checked each of them! ). If i insert a third texture into the shader the first is still not visible, but the second and the third are. Of course if i use only one texture, the texture is visible. Also it seems like its not the texture itself, all are RGB565 and if i switch the order in which they are loaded always the last one is working.
This looks like a error somehow, but this error is completly new, before switching to MRT the shaders worked.
The Shader
varying vec3 vNormal;
varying vec2 vUV0;
varying mat3 vTangentToWorld;
uniform float uRoughness;
uniform float uMetallic;
uniform sampler2D uDiffuse;
uniform sampler2D uDiffuse2;
uniform sampler2D uNormals;
void PS_SHADER() // PS_SHADER is defined as main
{
vec4 diffuse = texture2D(uDiffuse2, vUV0) * uRoughness + (1 - uRoughness) * texture2D(uDiffuse, vUV0);
vec3 specular = (diffuse.xyz * uMetallic) + (uSpecular * (1 - uMetallic));
vec3 normalTexture = texture2D(uNormals, vUV0).rgb * 2.0 - 1.0;
vec3 normal = normalTexture * vTangentToWorld;
// Output the data into the deferred pipeline
// Color component
gl_FragData[0] = vec4((diffuse * (1 - uMetallic)).xyz, diffuse.a);
// Normal and roughness
gl_FragData[1] = vec4((normalize(normal) + 1) / 2, uRoughness);
// Specular component
gl_FragData[2] = vec4(specular, UNUSED);
}
MRT setup
The MRT is working. I generate a framebuffer and attach 4 textures for rendering to it bound to GL_COLOR_ATTACHMENT0 to GL_COLOR_ATTACHMENT2 and of course i have a GL_DEPTH_ATTACHMENT.
Before rendering i bind the target framebuffer ( glBindFramebuffer(GL_FRAMEBUFFER, _FramebufferHandle) ), and call glDrawBuffers with the color attachments only.
Related
I am currently writing a program with OpenSceneGraph (3.4.0) and my own glsl (330) shaders.
It uses multiple textures for input, then does a multiple render target rendering with a pre render camera and reads in those multiple render target textures with a second camera for deferred shading. Thus both cameras have their own shaders (called geometry_pass and lighting_pass here).
My problem: both shaders use the same textures in all sampler2D uniforms when reading.
//in geometry_pass.frag
uniform sampler2D uAlbedoMap;
uniform sampler2D uHeightMap;
uniform sampler2D uNormalMap;
uniform sampler2D uRoughnessMap;
uniform sampler2D uSpecularMap;
[...]
layout (location = 0) out vec4 albedo;
layout (location = 1) out vec4 height;
layout (location = 2) out vec4 normal;
layout (location = 3) out vec4 position;
layout (location = 4) out vec4 roughness;
layout (location = 5) out vec4 specular;
[...]
albedo = vec4(texture(uAlbedoMap, vTexCoords).rgb, 1.0);
height = vec4(texture(uHeightMap, vTexCoords).rgb, 1.0);
normal = vec4(texture(uNormalMap, vTexCoords).rgb, 1.0);
position = vec4(vPosition_WorldSpace, 1.0);
roughness = vec4(texture(uRoughnessMap, vTexCoords).rgb, 1.0);
specular = vec4(texture(uSpecularMap, vTexCoords).rgb, 1.0);
Here the output is always the color of the uAlbedoMapexcept for the position, which gets exported correctly.
In the lighting pass, when I read in the textures of the geometry pass, again all input textures are the same
//in lighting_pass.frag
uniform sampler2D uAlbedoMap;
uniform sampler2D uHeightMap;
uniform sampler2D uNormalMap;
uniform sampler2D uPositionMap;
uniform sampler2D uRoughnessMap;
uniform sampler2D uSpecularMap;
[...]
vec3 albedo = texture(uAlbedoMap, vTexCoord).rgb;
vec3 height = texture(uHeightMap, vTexCoord).rgb;
vec3 normal_TangentSpace = texture(uNormalMap, vTexCoord).rgb;
vec3 position_WorldSpace = texture(uPositionMap, vTexCoord).rgb;
vec3 roughness = texture(uRoughnessMap, vTexCoord).rgb;
vec3 specular = texture(uSpecularMap, vTexCoord).rgb;
i.e. the position map that was correctly exported has the color of the albedo in the lighting pass as well.
Thus, what seems to be working correctly is the texture output, but what is obviously not working is the input.
I have tried to debug this with CodeXL and there I can see that all the images for the geometry_pass have (at some point at least) been correctly bound, they're all visible. The output textures of the framebuffer object confirm that the position texture of the geometry_pass is correct.
As far as I can see when going step by step through this, the textures are correctly bound (i.e. the uniform locations are correct).
Now the obvious question: How can I get those textures to be correctly used in the shaders?
Construction of the program
The viewer is an osgViewer::Viewer, so there is only one view.
The scene graph is as follows:
The displayCamerais the camera from the viewer. Since I'm working with Qt (5.9.1), I reset the GraphicsContext before I do anything else with the scene graph.
osg::ref_ptr<osg::Camera> camera = viewer.getCamera();
osg::ref_ptr<osg::GraphicsContext::Traits> traits = new osg::GraphicsContext::Traits;
traits->windowDecoration = false;
traits->x = 0;
traits->y = 0;
traits->width = 640;
traits->height = 480;
traits->doubleBuffer = true;
camera->setGraphicsContext(new osgQt::GraphicsWindowQt(traits.get()));
camera->getGraphicsContext()->getState()->setUseModelViewAndProjectionUniforms(true);
camera->getGraphicsContext()->getState()->setUseVertexAttributeAliasing(true);
camera->setClearMask(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
camera->setClearColor(osg::Vec4(0.2f, 0.2f, 0.6f, 1.0f));
camera->setViewport(new osg::Viewport(0, 0, traits->width, traits->height));
camera->setViewMatrix(osg::Matrix::identity());
I then set displayCamera to this viewer camera, create a second camera for render to texture (thus called rttCamera) and add it as a child to the displayCamera. I add the scene (consisting out of agroup node containing a geode containing a hardcoded geometry) to the rttCamera and in the end create a screen quad geometry (below a geode, which in turn is child of matrix transform; this matrix transform is what is added as a child to displayCamera).
Thus the displayCamera has the two children rttCamera and the matrixtransform->screenQuad. The rttCamera has the child scene->geode.
Both cameras have their own rendermask, the screen quad uses the displayCameras rendermask, the scene the rttCameras rendermask.
With the scene node I read in 5 Textures from file (all bitmaps) and then render the rttCamera into the Framebuffer Object with multiple render targets (for deferred shading).
//model is the geode in the scene group node
osg::ref_ptr<osg::StateSet> ss = model->getOrCreateStateSet();
ss->addUniform(new osg::Uniform(name.toStdString().c_str(), counter));
ss->setTextureAttributeAndModes(counter, pairNameTexture.second, osg::StateAttribute::ON | osg::StateAttribute::PROTECTED);
.
//camera is the rttCamera
//bufferComponent is constructed by osg::Camera::COLOR_BUFFER0+counter
//(where counter is just an integer that gets incremented)
//texture is an osg::Texture2D that is newly created
camera->attach(bufferComponent, texture);
//the textures get stored to assign them later on
gBufferTextures[name] = texture;
These mrt textures are bound to the screenquad as textures
//ssQuad is the stateset of the screen quad geode
QString uniformName = "u" + name + "Map";
uniformName[1] = uniformName[1].toUpper();
ssQuad->addUniform(new osg::Uniform(uniformName.toStdString().c_str(), counter));
osg::ref_ptr<osg::Texture2D> tex = gBufferTextures[name];
ssQuad->setTextureAttributeAndModes(counter, gBufferTextures[name], osg::StateAttribute::ON | osg::StateAttribute::OVERRIDE);
other set ups are the rendertarget (FBO for rttCamera, Framebuffer for displayCamera), lighting (off in both cameras). the rttCamera gets the same graphics context that it is created for the displaycamera (i.e. the graphics context object is passed to the rttCamera and set as its own graphics context).
The texture attachments are created as follows (where there is no difference in using width and height or the power-of-2 values for size)
osg::ref_ptr<osg::Texture2D> Utils::createTextureAttachment(int width, int height)
{
osg::Texture2D* texture = new osg::Texture2D();
//texture->setTextureSize(width, height);
texture->setTextureSize(512, 512);
texture->setInternalFormat(GL_RGBA);
texture->setFilter(osg::Texture2D::MIN_FILTER, osg::Texture2D::LINEAR);
texture->setFilter(osg::Texture2D::MAG_FILTER, osg::Texture2D::LINEAR);
return texture;
}
Let me know if there is more crucial-for-solving code or information missing.
So I finally found the error. My counter has been an unsigned int which apperantly is not allowed. Since osg is hiding so much of the errors from me, I didn't see that this was an issue...
After changing it to just a normal int, I now get different textures into my shader.
I'm working on shadows for a 2D overhead game. Right now, the shadows are just sprites with the color (0,0,0,0.1) drawn on a layer above the tiles.
The problem: When many entities or trees get clumped together, the shadows overlap, forming unnatural-looking dark areas.
I've tried drawing the shadows to a framebuffer and using a simple shader to prevent overlapping, but that lead to other problems, including layering issues.
Is it possible to enable a certain blend function for the shadows that prevents "stacking", or a better way to use a shader?
If you don't want to deal with sorting issues, I think you could do this with a shader. But every object will have to be either affected by shadow or not. So tall trees could be marked as not shadow receiving, while the ground, grass, and characters would be shadow receiving.
First make a frame buffer with clear color white. Draw all your shadows on it as pure black.
Then make a shadow mapping shader to draw everything in your world. This relies on you not needing all four channels of the sprite's color, because we need one of those channels to mark each sprite as shadow receiving or not. For example, if you aren't using RGB to tint your sprites, we could use the R channel. Or if you aren't fading them in and out, we could use A. I'll assume the latter here:
Vertex shader:
attribute vec4 a_position;
attribute vec4 a_color;
attribute vec2 a_texCoord0;
varying vec2 v_texCoords;
varying vec2 v_texCoordsShadowmap;
varying vec4 v_color;
uniform mat4 u_projTrans;
void main()
{
v_texCoords = a_texCoord0;
v_color = a_color;
v_color.a = v_color.a * (255.0/254.0); //this is a correction due to color float precision (see SpriteBatch's default shader)
vec3 screenPosition = u_projTrans * a_position;
v_texCoordsShadowmap = (screenPosition.xy * 0.5) + 0.5;
gl_Position = screenPosition;
}
Fragment shader:
#ifdef GL_ES
precision mediump float;
#endif
varying vec2 v_texCoords;
varying vec2 v_texCoordsShadowmap;
varying vec4 v_color;
uniform sampler2D u_texture;
uniform sampler2D u_textureShadowmap;
void main()
{
vec4 textureColor = texture2D(u_texture, v_texCoords);
float shadowColor = texture2D(u_textureShadowmap, v_texCoordsShadowmap).r;
shadowColor = mix(shadowColor, 1.0, v_color.a);
textureColor.rgb *= shadowColor * v_color.rgb;
gl_FragColor = textureColor;
}
These are completely untested and probably have bugs. Make sure you assign the frame buffer's color texture to "u_textureShadowmap". And for all your sprites, set their color's alpha based on how much shadow you want them to have cast on them, which will generally always be 0 or 0.1 (based on the brightness you were using before).
Draw your shadows to fbo with disabled blending.
Draw background e.g. grass
Draw shadows texture from fbo
Draw all other sprites
I have written a fragment shader which i would like to change the color of the fragment. for example I would like if the color it receives is black then it should change it to a blue.
This is the shader that I am using:
uniform sampler2D mytex;
layout (pixel_center_integer) in vec4 gl_FragCoord;
uniform sampler2D texture1;
void main ()
{
ivec2 screenpos = ivec2 (gl_FragCoord.xy);
vec4 color = texelFetch (mytex, screenpos, 0);
if (color == vec4 (0.0,0.0,0.0,1.0)) {
color = (0.0,0.0,0.0,0.0);
}
gl_FragColor = texture2D (texture1, gl_TexCoord[0].st);
}
And here is the log that I am getting from it:
WARNING: -1:65535: 'GL_ARB_explicit_attrib_location' : extension is not available in current GLSL version
WARNING: 0:1: 'texelFetch' : function is not available in current GLSL version
I am aware of the warning- but shouldn't it compile anyways?
The shader is not doing what i would like it to do, can someone explain why?
For one thing, you are using functions that are not available in your GLSL implementation. The result of calling these will be undefined.
However, the kicker here is that gl_FragColor has absolutely NOTHING to do with the value of color in this shader. So even if your texelFetch (...) logic actually did work correctly, changing the value of color does nothing to the final output. A smart compiler will see this as a no-op and effectively strip your shader down to this:
uniform sampler2D texture1;
void main ()
{
gl_FragColor = texture2D (texture1, gl_TexCoord[0].st);
}
If that were not enough, texelFetch (...) is completely unnecessary in this shader. If you want to lookup the texel that corresponds to the current fragment in your shader and the texture has the same dimensions as the viewport you are drawing into you can actually use texture2D (texture1, gl_FragCoord.xy); This is because the default behaviour in GLSL is to have gl_FragCoord supply the coordinate of the fragment's center (x+0.5, y+0.5) - this is also the center of the corresponding texel in your texture (if it is the same resolution), so you can do a traditional texture lookup without worrying that texture filtering will alter your sampled result.
texelFetch (...) lets you fetch an explicit texel in a texture without using normalized coordinates, it is sort of like a "grownup" rectangle texture :) It is generally useful if you are using a multisample texture and want a specific sample, or if you want to bypass texture filtering (which includes mipmap level selection). In this case, it is not needed at all.
This is probably what you really want (OpenGL 3.2):
#version 150
uniform sampler2D mytex;
uniform sampler2D texture1;
layout (location=0) out vec4 frag_color;
layout (location=1) out vec4 mytex_color;
void main ()
{
mytex_color = texture2D (mytex, gl_FragCoord.xy);
// This is not black->blue like you explained in your question...
// ... This is generally opaque->transparent, assuming 4th component = alpha
if (mytex_color == vec4 (0.0,0.0,0.0,1.0)) {
mytex_color = vec4 (0.0);
}
frag_color = texture2D (texture1, gl_TexCoord[0].st);
}
In older GLSL versions, you will have to use glBindFragDataLocation (...) and set the data locations manually or use gl_FragData[n] instead of out variables.
Now the real problem here is that you seem to be wanting to change the color of the texture you are sampling from. That will not work, at best you will have to use two fragment data outputs. Writing into the same texture you are sampling from can be done under some very controlled circumstances, but generally what you would do is ping-pong between textures. In other words, you would fetch from one texture, write to another texture and all subsequent render passes that reference to the original texture should be swapped with the one you just wrote to.
See "Fragment Data Location" for more information on Multiple Render Target drawing.
Have a strange issue with my glsl shader. It renders nothing (eg black screen) and makes my glDrawElements cast a GL_INVALID_OPERATION. The shader in use is shown bellow. When I comment out the line with v = texture3D(texVol,pos).r; and replace it with v = 0.4; it outputs what is expected (orange-like color) and no gl errors is generated.
uniform sampler2D texBack;
uniform sampler3D texVol;
uniform vec3 texSize;
uniform vec2 winSize;
uniform float iso;
varying vec3 inCoords;
vec4 raytrace(in vec3 entryPoint,in vec3 exitPoint){
vec3 dir = exitPoint - entryPoint;
vec3 pos = entryPoint;
vec4 color = vec4(0.0,0.0,0.0,0.0);
int steps = int(2.0*length(texSize));
dir = dir * (1.0/steps);
vec3 n;
float v,m=0.0,avg=0.0,avg2=0.0;
for(int i = 0;i<steps || i < 2500;i++){
v = texture3D(texVol,pos).r;
m = max(v,m);
avg += v;
pos += dir;
}
return vec4(avg/steps,m,0,1);
}
void main()
{
vec2 texCoord = gl_FragCoord.xy/winSize;
vec3 exitPoint = texture2D(texBack,texCoord).xyz;
gl_FragColor = raytrace(inCoords,exitPoint);
}
I am using an VBO for rendering a color cube as entry and exist point for my rays. They are stored in FBOs and they look ok when I render them directly to the screen.
I have tried chaning to glBegin/glEnd and draw the cube with quads and then I get the same errors.
I cant find what I am doing wrong and now I need your help. Why is my texture3D generating GL_INVALID_OPERATION?
Note:
I have enabled both 2d and 3d textures.
Edit:
I've just uploaded the whole project to github. browse to for more code https://github.com/r-englund/rGraphicsLibrary
This is tested on both Intel HD 3000 and Nvidia GT550m
According to OpenGL specification glDrawElements() generates GL_INVALID_OPERATION in the following cases:
If a geometry shader is active and mode is incompatible with the input primitive type of the geometry shader in the currently installed program object.
If a non-zero buffer object name is bound to an enabled array or the element array and the buffer object's data store is currently mapped.
This means the problem has nothing to do with your fragment shader. If you don't use geometry shaders, you should fix the buffer objects accordingly.
It looks like your are not providing additional relevant information in your question.
What is the correct way of doing the following:
Render a scene into a texture using a FBO (fbo-a)
Then apply an effect using the texture (tex-a) and render this into another texture (tex-b) using the same fbo (fbo-a)
Then render this second texture, with the applied effect (tex-b) as a full screen quad.
My approach is this, but this gives me a texture filled with "noise" on window + the applied effect (all pixels are randomly colored red, green, blue white, black).
I'm using one FBO, with two textures set to GL_COLOR_ATTACHENT0 (tex-a) and GL_COLOR_ATTACHMENT1 (tex-b)
I bind my fbo, make sure it's rendered into the tex-a using glDrawBuffer(GL_COLOR_ATTACHMENT0)
Then I apply the effect in a shader with tex-a bound and set as 'sampler2D'. Using texture unit 1, and switch to the second color attachment (glDrawBuffer(GL_COLOR_ATTACHMENT1)). and render a full screen quad. Everything is now rendered into tex-b
Then I switch back to the default FBO (0) and use tex-b with a full screen quad to render the result.
Example of the result when applying my shader
This is the shader I'm using. I'm not aware this could be what is causing this, but maybe the noise is caused by a overflow?
Vertex shader
attribute vec4 a_pos;
attribute vec2 a_tex;
varying vec2 v_tex;
void main() {
mat4 ident = mat4(1.0);
v_tex = a_tex;
gl_Position = ident * a_pos;
}
Fragment shader
uniform int u_mode;
uniform sampler2D u_texture;
uniform float u_exposure;
uniform float u_decay;
uniform float u_density;
uniform float u_weight;
uniform float u_light_x;
uniform float u_light_y;
const int NUM_SAMPLES = 100;
varying vec2 v_tex;
void main() {
if (u_mode == 0) {
vec2 pos_on_screen = vec2(u_light_x, u_light_y);
vec2 delta_texc = vec2(v_tex.st - pos_on_screen.xy);
vec2 texc = v_tex;
delta_texc *= 1.0 / float(NUM_SAMPLES) * u_density;
float illum_decay = 1.0;
for(int i = 0; i < NUM_SAMPLES; i++) {
texc -= delta_texc;
vec4 sample = texture2D(u_texture, texc);
sample *= illum_decay * u_weight;
gl_FragColor += sample;
illum_decay *= u_decay;
}
gl_FragColor *= u_exposure;
}
else if(u_mode == 1) {
gl_FragColor = texture2D(u_texture, v_tex);
gl_FragColor.a = 1.0;
}
}
I've read this FBO article on opengl.org, where they describe a feedback loop at the bottom of the article. The description is not completely clear to me and I'm wondering if I'm exactly doing what they describe there.
Update 1:
Link to source code
Update 2:
When I first set gl_FragColor.rgb = vec3(0.0, 0.0, 0.0); before I start the sampling loop (with NUM_SAMPLES), it works find. No idea why though.
The problem is that you're not initializing gl_FragColor, and you're modifying it with the lines
gl_FragColor += sample;
and
gl_FragColor *= u_exposure;
both of which depend on the previous value of gl_FragColor. So you're getting some random junk (whatever happened to be in the register that the shader compiler decided to use for the gl_FragColor computation) added in. This has a strong possibility of working fine on some driver/hardware combinations (because the compiler decided to use a register that was always 0 for some reason) and not on others.