Schedule Syllabus Resources

Texture code

Your repository will contain a 'Textures' template code. Fill in all the TODO blocks and map the Rose-Hulman image to the model. You will need to:

• Set the texture coordinates for the model
• Specify and upload the texture image data
• Activate and use a texture unit when rendering
• Make the shader use the texture coordinates and data

Hints

• You can adjust the view with the mouse.
• A wireframe outline of the model is also rendered. This can help you visualize the triangle boundaries.
• You can have the shader display the texture coordinates to make sure the are what you intend.
• Use these CPU side setup functions: glGenTextures, glBindTexture, glTexParameterf, glTexImage2D, glGenerateMipmap.
• Use these CPU side render functions: glActiveTexture.
• Use these GPU side render functions: texture.

Code

The code from in class:

RenderEngine.h : display()

//TODO bind the texture object
glBindTexture(GL_TEXTURE_2D, textures[i]);

//TODO activate a texture unit
GLint texUnitId = 0;
glActiveTexture(GL_TEXTURE0+texUnitId);

//TODO bind the sampler to a texture unit
glUniform1i(glGetUniformLocation(shaderProg[0], "texUnit"), texUnitId);

glDrawArrays(GL_TRIANGLES, 6*i, 6);

glBindTexture(GL_TEXTURE_2D, 0);

RenderEngine.h : setupTextures()

//TODO bind a texture object
glBindTexture(GL_TEXTURE_2D, textures[i]);

//TODO set min/mag sampling parameters
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
//glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
//glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);

glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
//glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

//TODO set edge wrap parameters
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
//glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_MIRRORED_REPEAT);
//glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_MIRRORED_REPEAT);
//glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
//glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

//TODO upload texture and generate mipmap
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texSizeX, texSizeY, 0, GL_RGBA, GL_UNSIGNED_BYTE, texData);
bool  mipmapEnabled = true;
if(mipmapEnabled)
{
	//mip mapping, upload 0 level, then build maps
	glGenerateMipmap(GL_TEXTURE_2D);
}
else
{
	//no mip mapping, upload 0 level only
}

//TODO unbind the texture
glBindTexture(GL_TEXTURE_2D, 0);

simple.frag

//TODO upload a uniform sampler2D texture sampler id
uniform sampler2D texSampler;
...
//TODO use the texture() function with uploaded sampler id to get a texture color
fragColor = texture(texSampler, texMapping);

Rubric

Texture rectangle with Rose-Hulman image

0: No texturing

5: Texture uploaded and used, but coords incorrect

10: Correct image displayed

Example

This image is everything working with the default texture coordinates:


This image is everything working: