There are a lot of answers for similar questions around, but I can't find a solution that works for me.
I have a scene with multiple mesh in, each with the following draw call:
shader.use();
for (unsigned int i = 0; i < textures.size(); i++)
{
glActiveTexture(GL_TEXTURE0 + i);
glBindTexture(GL_TEXTURE_2D, textures[i].id);
}
for (unsigned int i = 0; i < textures.size(); i++)
{
glUniform1f(glGetUniformLocation(shader.ID, material_uniforms[i].c_str()), i);
}
glActiveTexture(GL_TEXTURE0);
// draw mesh
glBindVertexArray(VAO);
glDrawElements(GL_TRIANGLES, indices.size(), GL_UNSIGNED_INT, 0);
glBindVertexArray(0);
and my frag shader uniforms (amongst others) are:
uniform sampler2D texture_ambient1;
uniform sampler2D texture_diffuse1;
uniform sampler2D texture_specular1;
uniform sampler2D texture_bump1;
uniform sampler2D texture_dissolve1;
In RenderDoc, although in the Resource Inspector all the textures seem to be listed, the "Inputs" in Texture Viewer (FS 0[0] texture_ambient1, FS 1[0] texture_diffuse1, FS 2[0] texture_dissolve1 and FS 3[0] texture_specular1 (I don't know where my other "texture_bump1" has gone?)) for each draw call seem to be exactly the same texture.
Also in RenderDoc under "Pipeline State" and the FS Stage, the Textures and Samplers each only have one bound item? Seems to contradict the fact RenderDoc sees all the above inputs?
Am I doing something obviously wrong in my code?
Looks like you're trying to bind the texture unit using glUniform1f but the texture unit index is an integer (not a float), so you should be using glUniform1i to set that uniform.
glUniform1i(glGetUniformLocation(shader.ID, material_uniforms[i].c_str()), i);
Related
I'm trying to set up deferred rendering, and have successfully managed to output data to the varying gbuffer textures (position, normal, albedo, specular).
I am now attempting to sample from the albedo texture to a 5th colour attachment in the same fbo (for the purposes of further potential post process sampling), by rendering a full screen quad with simple texture coordinates.
I have checked that the vertex/texcoord data is good via Nsight, and confirmed that the shader can "see" the texture to sample from, but all that I see in the target texture is the clear colour when I examine it in the Nsight debugger.
At the moment, the shader is basically just a simple pass through shader:
vertex shader:
#version 430
in vec3 MSVertex;
in vec2 MSTexCoord;
out xferBlock
{
vec3 VSVertex;
vec2 VSTexCoord;
} outdata;
void main()
{
outdata.VSVertex = MSVertex;
outdata.VSTexCoord = MSTexCoord;
gl_Position = vec4(MSVertex,1.0);
}
fragment shader:
#version 430
layout (location = 0) uniform sampler2D colourMap;
layout (location = 0) out vec4 colour;
in xferBlock
{
vec3 VSVertex;
vec2 VSTexCoord;
} indata;
void main()
{
colour = texture(colourMap, indata.VSTexCoord).rgba;
}
As you can see, there is nothing fancy about the shader.
The gl code is as follows:
//bind frame buffer for writing to texture #5
glBindFramebuffer(GL_FRAMEBUFFER, fbo);
glDrawBuffer(GL_COLOR_ATTACHMENT4); //5 textures total
glClear(GL_COLOR_BUFFER_BIT);
//activate shader
glUseProgram(second_stage_program);
//bind texture
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, fbo_buffers[2]); //third attachment: albedo
//bind and draw fs quad (two array buffers: vertices, and texture coordinates)
glBindVertexArray(quad_vao);
glDrawArrays(GL_TRIANGLES,0,6);
I'm trying to work out what is preventing rendering to the texture. I'm using a core context with OpenGL v4.3.
I've tried outputting a single white colour for all fragments, using the texture coordinates to generate a colour colour = vec4(indata.VSTexCoord, 1.0, 1.0); and sampling the texture itself, as you see in the shader code, but nothing changes the resultant texture, which just shows the clear colour.
What am I doing wrong?
I am trying to understand this code:
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texture1);
glUniform1i(glGetUniformLocation(ourShader.Program, "ourTexture1"), 0);
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, texture2);
glUniform1i(glGetUniformLocation(ourShader.Program, "ourTexture2"), 1);
This is the related shader code:
#version 330 core
...
uniform sampler2D ourTexture1;
uniform sampler2D ourTexture2;
void main()
{
color = mix(texture(ourTexture1, TexCoord), texture(ourTexture2, TexCoord), 0.2);
}
So, as far as I understand, after activating GL_TEXTURE0 we bind texture1 to it. My understanding is that this binds texture1 to first sampler2d.The part I dont understand is, why do we need to use glUniform call.
It's an indirection. You choose the texture that is input at location GL_TEXTURE0 then you tell the uniform in your shader to fetch its texture from that same location. It's kind of like this (apologies for the diagram).
The first row is texture unit locations and the second row is shader uniform locations. You may want to bind texture unit 4 to shader sampler 2, for example.
(DatenWolf will be along in a moment to correct me :).
I am using freeglut, GLEW and DevIL to render a textured teapot using a vertex and fragment shader. This is all working fine in OpenGL 2.0 and GLSL 1.2 on Ubuntu 14.04.
Now, I want to apply a bump map to the teapot. My lecturer evidently doesn't brew his own tea, and so doesn't know they're supposed to be smooth. Anyway, I found a nice-looking tutorial on old-school bump mapping that includes a fragment shader that begins:
uniform sampler2D DecalTex; //The texture
uniform sampler2D BumpTex; //The bump-map
What they don't mention is how to pass two textures to the shader in the first place.
Previously I
//OpenGL cpp file
glBindTexture(GL_TEXTURE_2D, textureHandle);
//Vertex shader
gl_TexCoord[0] = gl_TextureMatrix[0] * gl_MultiTexCoord0;
//Fragment shader
gl_FragColor = color * texture2D(DecalTex,gl_TexCoord[0].xy);
so now I
//OpenGL cpp file
glBindTexture(GL_TEXTURE_2D, textureHandle);
glBindTexture(GL_TEXTURE_2D, bumpHandle);
//Vertex shader
gl_TexCoord[0] = gl_TextureMatrix[0] * gl_MultiTexCoord0;
gl_TexCoord[1] = gl_TextureMatrix[1] * gl_MultiTexCoord1;
//Fragment shader
gl_FragColor = color * texture2D(BumpTex,gl_TexCoord[0].xy);
//no bump logic yet, just testing I can use texture 1 instead of texture 0
but this doesn't work. The texture disappears completely (effectively the teapot is white). I've tried GL_TEXTURE_2D_ARRAY, glActiveTexture and few other likely-seeming but fruitless options.
After sifting through the usual mixed bag of references to OpenGL and GLSL new and old, I've come to the conclusion that I probably need glGetUniformLocation. How exactly do I use this in the OpenGL cpp file to pass the already-populated texture handles to the fragment shader?
How to pass an array of textures with different sizes to GLSL?
Passing Multiple Textures from OpenGL to GLSL shader
Multiple textures in GLSL - only one works
(This is homework so please answer with minimal code fragments (if at all). Thanks!)
Failing that, does anyone have a tea cosy mesh?
It is very simple, really. All you need is to bind the sampler to some texture unit with glUniform1i. So for your code sample, assuming the two uniform samplers:
uniform sampler2D DecalTex; // The texture (we'll bind to texture unit 0)
uniform sampler2D BumpTex; // The bump-map (we'll bind to texture unit 1)
In your initialization code:
// Get the uniform variables location. You've probably already done that before...
decalTexLocation = glGetUniformLocation(shader_program, "DecalTex");
bumpTexLocation = glGetUniformLocation(shader_program, "BumpTex");
// Then bind the uniform samplers to texture units:
glUseProgram(shader_program);
glUniform1i(decalTexLocation, 0);
glUniform1i(bumpTexLocation, 1);
OK, shader uniforms set, now we render. To do so, you will need the usual glBindTexture plus glActiveTexture:
glActiveTexture(GL_TEXTURE0 + 0); // Texture unit 0
glBindTexture(GL_TEXTURE_2D, decalTexHandle);
glActiveTexture(GL_TEXTURE0 + 1); // Texture unit 1
glBindTexture(GL_TEXTURE_2D, bumpHandle);
// Done! Now you render normally.
And in the shader, you will use the textures samplers just like you already do:
vec4 a = texture2D(DecalTex, tc);
vec4 b = texture2D(BumpTex, tc);
Note: For techniques like bump-mapping, you only need one set of texture coordinates, since the textures are the same, only containing different data. So you should probably pass texture coordinates as a vertex attribute.
instead of using:
glUniform1i(decalTexLocation, 0);
glUniform1i(bumpTexLocation, 1);
in your code,
you can have:
layout(binding=0) uniform sampler2D DecalTex;
// The texture (we'll bind to texture unit 0)
layout(binding=1)uniform sampler2D BumpTex;
// The bump-map (we'll bind to texture unit 1)
in your shader. That also mean you don't have to query for the location.
I have OpenGL program that I want to texture sphere with bitmap of earth. I prepared mesh in Blender and exported it to OBJ file. Program loads appropriate mesh data (vertices, uv and normals) and bitmap properly- I have checked it texturing cube with bone bitmap.
My program is texturing sphere, but incorrectly (or in the way I don't expect). Each triangle of this sphere includes deformed copy of this bitmap. I've checked bitmap and uv seems to be ok. I've tried many sizes of bitmap (powers of 2, multiples of 2 etc).
Here's the texture:
Screenshot of my program (like It would ignore my UV coords):
Mappings of UVs in Blender I've done in this way:
Code setting texture after loading it (apart from code adding texture to VBO- I think it's ok):
GLuint texID;
glGenTextures(1,&texID);
glBindTexture(GL_TEXTURE_2D,texID);
glTexImage2D(GL_TEXTURE_2D,0,GL_RGB,width,height,0,GL_BGR,GL_UNSIGNED_BYTE,(GLvoid*)&data[0]);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_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);
Is there needed any extra code to map this texture properly?
[Edit]
Initializing textures (earlier presented code is in LoadTextureBMP_custom() function)
bool Program::InitTextures(string texturePath)
{
textureID = LoadTextureBMP_custom(texturePath);
GLuint TBO_ID;
glGenBuffers(1,&TBO_ID);
glBindBuffer(GL_ARRAY_BUFFER,TBO_ID);
glBufferData(GL_ARRAY_BUFFER,uv.size()*sizeof(vec2),&uv[0],GL_STATIC_DRAW);
return true;
}
My main loop:
bool Program::MainLoop()
{
bool done = false;
mat4 projectionMatrix;
mat4 viewMatrix;
mat4 modelMatrix;
mat4 MVP;
Camera camera;
shader.SetShader(true);
while(!done)
{
if( (glfwGetKey(GLFW_KEY_ESC)))
done = true;
if(!glfwGetWindowParam(GLFW_OPENED))
done = true;
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// Tutaj przeksztalcenia macierzy
camera.UpdateCamera();
modelMatrix = mat4(1.0f);
viewMatrix = camera.GetViewMatrix();
projectionMatrix = camera.GetProjectionMatrix();
MVP = projectionMatrix*viewMatrix*modelMatrix;
// Koniec przeksztalcen
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D,textureID);
shader.SetShaderParameters(MVP);
SetOpenGLScene(width,height);
glEnableVertexAttribArray(0); // Udostepnienie zmiennej Vertex Shadera => vertexPosition_modelspace
glBindBuffer(GL_ARRAY_BUFFER,VBO_ID);
glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,0,(void*)0);
glEnableVertexAttribArray(1);
glBindBuffer(GL_ARRAY_BUFFER,TBO_ID);
glVertexAttribPointer(1,2,GL_FLOAT,GL_FALSE,0,(void*)0);
glDrawArrays(GL_TRIANGLES,0,vert.size());
glDisableVertexAttribArray(0);
glDisableVertexAttribArray(1);
glfwSwapBuffers();
}
shader.SetShader(false);
return true;
}
VS:
#version 330
layout(location = 0) in vec3 vertexPosition;
layout(location = 1) in vec2 vertexUV;
out vec2 UV;
uniform mat4 MVP;
void main()
{
vec4 v = vec4(vertexPosition,1.0f);
gl_Position = MVP*v;
UV = vertexUV;
}
FS:
#version 330
in vec2 UV;
out vec4 color;
uniform sampler2D texSampler; // Uchwyt tekstury
void main()
{
color = texture(texSampler, UV);
}
I haven't done any professional GL programming, but I've been working with 3D software quite a lot.
your UVs are most likely bad
your texture is a bad fit to project on a sphere
considering UVs are bad, you might want to check your normals as well
consider an ISOSPHERE instead of a regular one to make more efficient use of polygons
You are currently using a flat texture with flat mapping, which may give you very ugly results, since you will have very low resolution in the "outer" perimeter and most likely a nasty seam artifact where the two projections meet if you like... rotate the planet or something.
Note that you don't have to have any particular UV map, it just needs to be correct with the geometry, which it doesn't look like it is right now. The spherical mapping will take care for the rest. You could probably get away with a cylindrical map as well, since most Earth textures are in a suitable projection.
Finally, I've got the answer. Error was there:
bool Program::InitTextures(string texturePath)
{
textureID = LoadTextureBMP_custom(texturePath);
// GLuint TBO_ID; _ERROR_
glGenBuffers(1,&TBO_ID);
glBindBuffer(GL_ARRAY_BUFFER,TBO_ID);
glBufferData(GL_ARRAY_BUFFER,uv.size()*sizeof(vec2),&uv[0],GL_STATIC_DRAW);
}
There is the part of Program class declaration:
class Program
{
private:
Shader shader;
GLuint textureID;
GLuint VAO_ID;
GLuint VBO_ID;
GLuint TBO_ID; // Member covered with local variable declaration in InitTextures()
...
}
I've erroneously declared local TBO_ID that covered TBO_ID in class scope. UVs were generated with crummy precision and seams are horrible, but they weren't problem.
I have to admit that information I've supplied is too small to enable help. I should have put all the code of Program class. Thanks everybody who tried to.
I'm trying to write a simple shader which would add textures attached to FBOs. There is no problem with FBO initialization and such (I've tested it). The problem is I believe with
glActiveTexture(GL_TEXTURE0). It doesn't seem to be doing anything- here is my frag shader:
(but generally shader is called - I've tested that by putting gl_FragColor = vec4(0,1,0,1);
uniform sampler2D Texture0;
uniform sampler2D Texture1;
varying vec2 vTexCoord;
void main()
{
vec4 texel0 = texture2D(Texture0, gl_TexCoord[0].st);
vec4 vec = texel0;
gl_FragColor = texel0;
}
And in C++ code i have:
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, iFrameBufferAccumulation);
glDrawBuffer(GL_COLOR_ATTACHMENT0_EXT);
( Render something - it works fine to iTextureImgAccumulation texture attached to GL_COLOR_ATTACHMENT0_EXT )
glClear (GL_COLOR_BUFFER_BIT );
glEnable(GL_TEXTURE_RECTANGLE_NV);
glActiveTexture(GL_TEXTURE0);
glBindTexture( GL_TEXTURE_RECTANGLE_NV, iTextureImgAccumulation ); // Bind our frame buffer texture
xShader.setUniform1i("Texture0", 0);
glLoadIdentity(); // Load the Identity Matrix to reset our drawing locations
glTranslatef(0.0f, 0.0f, -2.0f);
xShader.bind();
glBegin(GL_QUADS);
glTexCoord2f(0,OPT.m_nHeight);
glVertex3f(-1,-1,0);
glTexCoord2f(OPT.m_nWidth,OPT.m_nHeight);
glVertex3f(1,-1,0);
glTexCoord2f(OPT.m_nWidth,0);
glVertex3f(1,1,0);
glTexCoord2f(0,0);
glVertex3f(-1,1,0);
glEnd();
glBindTexture( GL_TEXTURE_RECTANGLE_NV, NULL );
xShader.unbind();
Result: black screen (when displaying second texture and using shader (without using shader its fine). I'm aware that this shader shouldn't do much but he doesn't even display
the first texture.
I'm in the middle of testing things but idea is that after rendering to first texture
I would add first texture to the second one. To do this I imagine that this fragment shader
would work :
uniform sampler2D Texture0;
uniform sampler2D Texture1;
varying vec2 vTexCoord;
void main()
{
vec4 texel0 = texture2D(Texture0, gl_TexCoord[0].st);
vec4 texel1 = texture2D(Texture1, gl_TexCoord[0].st);
vec4 vec = texel0 + texel1;
vec.w = 1.0;
gl_FragColor = vec;
}
And whole idea is that in a loop tex2 = tex2 + tex1 ( would it be possible that i use tex2 in this shader to render to GL_COLOR_ATTACHMENT1_EXT which is attached to tex2 ?)
I've tested both xShader.bind(); before initializing uniform variables and after. Both cases - black screen.
Anyway for a moment, I'm pretty sure that there is some problem with initialization of sampler for textures (maybe cos they are attached to FBO)?
I've checked the rest and it works fine.
Also another stupid problem:
How can i render texture on whole screen ?
I've tried something like that but it doesn't work ( i have to translate a bit this quad )
glViewport(0,0 , OPT.m_nWidth, OPT.m_nHeight);
glBindTexture( GL_TEXTURE_RECTANGLE_NV, iTextureImg/*iTextureImgAccumulation*/ ); // Bind our frame buffer texture
glBegin(GL_QUADS);
glTexCoord2f(0,OPT.m_nHeight);
glVertex3f(-1,-1,0);
glTexCoord2f(OPT.m_nWidth,OPT.m_nHeight);
glVertex3f(1,-1,0);
glTexCoord2f(OPT.m_nWidth,0);
glVertex3f(1,1,0);
glTexCoord2f(0,0);
glVertex3f(-1,1,0);
glEnd();
Doesnt work with glVertex2f also..
Edit: I've checked out and I can initialise some uniform variables only textures are problematic.
I've changed order but it still doesn't work.:( Btw other uniforms values are working well. I've displayed texture I want to pass to shader too. It works fine. But for unknown reason texture sampler isn't initialized in fragment shader. Maybe it has something to do that this texture is glTexImage2D(GL_TEXTURE_RECTANGLE_NV, 0, GL_RGB16F /GL_FLOAT_R32_NV/, OPT.m_nWidth, OPT.m_nHeight, 0, GL_RED, GL_FLOAT, NULL); (its not GL_TEXTURE_2D)?
It's not clear what does your xShader.bind(), I can gues you do glUseProgram(...) there. But uniform variables (sampler index in your case) should be set up after the glUseProgram(...) is called. In this order:
glUseProgram(your_shaders); //probably your xShader.bind() does it.
GLuint sampler_idx = 0;
GLint location = glGetUniformLocation(your_shaders, "Texture0");
if(location != -1) glUniform1i(location, sampler_idx);
else error("cant, get uniform location");
glActiveTexture(GL_TEXTURE0 + sampler_idx);
glBindTexture(GL_TEXTURE_2D, iTextureImg);
and 'yes' you can render FBO texture and use it in shader in another context
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, your_fbo_id);
// render to FBO there
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
then use your FBO texture the same way as you use regular textures.
glActiveTexture(GL_TEXTURE0);
glBindTexture( GL_TEXTURE_RECTANGLE_NV, iTextureImgAccumulation ); // Bind our frame buffer texture
xShader.setUniform1i("Texture0", 0);
This is a rectangle texture.
uniform sampler2D Texture0;
This is a 2D texture. They are not the same thing. The sampler type must match the texture type. You need to use a samplerRect, assuming your version of GLSL supports that.