For my program I want to pass data into the vertex shader as unsigned bytes and then convert the bytes to a float value (between 0.0 and 1.0) for color in the vertex shader with something like this:
#version 330 core
layout (location = 0) in uvec3 aPos;
layout (location = 1) in uvec4 aColor;
out VS_OUT {
vec4 color;
} vs_out;
void main()
{
vs_out.color = vec4(float(aColor.r) / 255.0f, float(aColor.g) / 255.0f, float(aColor.b) / 255.0f, 1.0f); //alpha set to 1 temporarily
gl_Position = vec4(aPos, 1.0);
}
however it seems no matter how I do the constructors or operations it will always convert to 1.0 when the inputed byte values are anything except 0 (zero resulting in 0.0). How do I fix this so I will get the correct color values between 0.0 and 1.0? (or is this a bug with openGL 3.3?)
code to pass data in:
unsigned char test[] = {
0, 0, 0, 255, 1, 10, 255, 0, 255 //first 3 is position and next 4 is color but still outputs white
};
unsigned int VBO, VAO;
glGenBuffers(1, &VBO);
glGenVertexArrays(1, &VAO);
glBindVertexArray(VAO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(test), &test, GL_STATIC_DRAW);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 3, GL_UNSIGNED_BYTE, GL_FALSE, 9*sizeof(byte), 0);
glEnableVertexAttribArray(1);
glVertexAttribPointer(1, 4, GL_UNSIGNED_BYTE, GL_FALSE, 9 * sizeof(byte), (void*)(3 * sizeof(BYTE)));
glBindVertexArray(0);
...
// draw points
ourShader.use();// use pre-defined shaders
glBindVertexArray(VAO);
glDrawArrays(GL_POINTS, 0, 1);
I figured it out. I can just put the in values in the shader as a vec4 instead of uvec4 and set the vertex attribute to normalize and the program will convert it automatically:
vertex shader:
#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec4 aColor;
out VS_OUT {
vec4 color;
} vs_out;
void main()
{
vs_out.color = aColor;
gl_Position = vec4(aPos, 1.0);
}
program code:
byte test[] = {//unsigned char
0, 0, 0, 25, 100, 136, 255, 0, 255 // ouputs teal color (index 3-6)
};
...
glEnableVertexAttribArray(1);
glVertexAttribPointer(1, 4, GL_UNSIGNED_BYTE, GL_TRUE, (9 * sizeof(byte)), (void*)(3 * sizeof(BYTE)));