Passing a texture to a shader

[Viking86]

Greetings, I've posted a similar question in the beginners forum, but it may be more appropriate in the advanced section.

I would like to implement relief mapping (which is similar to parallax but better ), i have the required GLSL code (.vert and .frag) from this example.
http://www.codesampler.com/source_users ... apping.zip

I have read the shader tutorial, however I am unsure how to pass the required textures to the shader. There is no inbuilt type of material with a heightmap as a second texture. (following the code of making a new material from the shade tutorial)

I need to pass a texture and a heightmap to the shader, any ideas on how to acomplish this?

Best regards, Daniel.

[ent1ty]

node->setMaterialTexture(0, texture);
node->setMaterialTexture(1, heighmap);

Then you should be able to access them in the shader.

[stefbuet]

And you have to give textures layer ID to the shader with the shader call back which send all uniform values.

[Viking86]

Thank you for your reply
I assume i need to use the
virtual void IMaterialRendererServices::setVertexShaderConstant and
IMaterialRendererServices::setPixelShaderConstant methods
in the class MyShaderCallBack : public video::IShaderConstantSetCallBack
from the shader tutorial.

what do I put as the parameters?
The first parameter is the texture i assume, one of the shaders needs 2 textures. I'm not sure about the startregister parameter though?

[freetimecoder]

First, you set the textures as described:

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node->setMaterialTexture(0, texture);
node->setMaterialTexture(1, heighmap);

In the shader callback, you now have to set the constants, depending on the uniforms in your shader. It says

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uniform sampler2D testTexture;
uniform sampler2D HeightTexture;

So your shader expects two textures. You can set a texture like this:

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int texture_height=1; 
services->setPixelShaderConstant("HeightTexture", (float*)(&texture_height), 1);

The other texture is set in the same way, you just have to change the parameters:

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int texture_test=0; 
services->setPixelShaderConstant("testTexture", (float*)(&texture_test), 1);

The order of the given parameters is not important, however it is better to give them in the right order, in this case it would be:

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int texture_test=0; 
services->setPixelShaderConstant("testTexture", (float*)(&texture_test), 1);
int texture_height=1; 
services->setPixelShaderConstant("HeightTexture", (float*)(&texture_height), 1);

This way it is easier to maintain an overview of the parameters.
greetings

[Viking86]

Thank you in you replies

now going through the shader code there are a few more things these particular shaders need.

uniform vec4 Tangent;
uniform vec4 Normal;
uniform vec4 BiNormal;

uniform vec4 Eye; //eye coord
varying vec3 EyeDir; // eye vector direction

I know how to get these in opengl, is this posible in irrilicht?

[slavik262]

Tangents, normals, and the like should be passed in automatically since that data is coming from the vertices themselves. To set other things, you use a class derived from IShaderConstantSetCallBack and set the data with IMaterialRendererServices functions. See the shader example for details.

[Viking86]

Tangents, normals, and the like should be passed in automatically since that data is coming from the vertices themselves. To set other things, you use a class derived from IShaderConstantSetCallBack and set the data with IMaterialRendererServices functions. See the shader example for details.

I don't think that they are passed automaticly, a quote from the "per pixel lightnig tutorial" for using parallax mapping (I also have a shader for that)

But just setting color and normal map is not everything. The material we want to use needs some additional informations per vertex like tangents and binormals. Because we are too lazy to calculate that information now, we let Irrlicht do this for us.That's why we call IMeshManipulator::createMeshWithTangents().
It creates a mesh copy with tangents and binormals from another mesh. After we've done that, we simply create a standard mesh scene node with this mesh copy, set color and normal map and adjust some other material settings.

And I don't know how to access irrilicht internal parallax shader routine

[slavik262]

In the example you take a mesh without tangents and use the mesh manipulator to create a duplicate mesh with tangents, but notice how in the tutorial itself, CD3D9ParallaxMapRenderer.cpp, and COpenGLParallaxMapRenderer.cpp, there's nothing that sets the tangents in a shader callback or anything. That's because these tangents are part of the vertex information (since each vertex has one). They get passed in automatically just like position, normal, color, and UV coordinates.

[Viking86]

In the example you take a mesh without tangents and use the mesh manipulator to create a duplicate mesh with tangents, but notice how in the tutorial itself, CD3D9ParallaxMapRenderer.cpp, and COpenGLParallaxMapRenderer.cpp, there's nothing that sets the tangents in a shader callback or anything. That's because these tangents are part of the vertex information (since each vertex has one). They get passed in automatically just like position, normal, color, and UV coordinates.

Thank you very much slavik, could my problem simply be in the names in the shader code ?

I found what the uniform variables are in the shader example, RenderMonkey helped me out
Tangent (1.0,0.0,0.0,0.0)
Normal((0.0,0.0,1.0,0.0))
BiNormal(0.0,1.0,0.0,0.0)
Eye(0.0,0.0,0.0,1.0)

Now I need to pass these to the fragment shader, something similar to this i assume
video::SColorf normala(0.0f,0.0f,1.0f,0.0f);
services->setVertexShaderConstant("Normal", reinterpret_cast<f32*>(&normala), 4);

Now I am not sure if ScolorF is the best way to do this but this is my result



Thanks again to everyone who helped !
p.s this is parallax map, relief mapping is just a bit different shader code but it is slow as hell on my laptop (1 fps)