Hi,
I am trying to define my own texture but struggling to get even a simple test to work. I have been hitting my head against the wall all day unable to move past this issue (I am sure you remember the feeling) so any help would be gratefully appreciated.
-> I am just seeing a black box where the texture colour should be (in this simple test I am just expecting a white box in the middle of the screen)
->There is no error from glGetError() and the shader compiles and links without giving an error.
->In the fragment shader if I comment out the texture line and instead just return a vec4 then it will display a solid colour with no problem
I have posted the essential elements of the code below. Can anyone spot what I am missing?
//Position vertices and texture coordinates for a box
GLfloat screen2DVertices[] =
{ //x, y, z //u, v
-0.8f, -0.8f, 0.0f, 0.0f, 0.0f, // bottom left corner
-0.8f, 0.8f, 0.0f, 0.0f, 1.0f, // top left corner
0.8f, 0.8f, 0.0f, 1.0f, 1.0f, // top right corner
0.8f, -0.8f, 0.0f, 1.0f, 0.0f, // bottom right corner
};
GLushort screen2DIndices[] =
{
0,1,2, // first triangle (bottom left - top left - top right)
0,2,3 // second triangle (bottom left - top right - bottom right)
};
//Texture width in pixels
const int TEXTURE_WIDTH = 32;
const int TEXTURE_HEIGHT = 32;
//3 RGB values per pixel
float texturePixels[TEXTURE_WIDTH * TEXTURE_HEIGHT * 3];
//Test with all white r = g = b = 1.0f
for (int i = 0; i < TEXTURE_WIDTH * TEXTURE_HEIGHT * 3; i++)
{
texturePixels[i] = 1.0f;
}
GLuint vao;
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
// Load texture
GLuint tex;
glGenTextures(1, &tex);
glBindTexture(GL_TEXTURE_2D, tex);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, TEXTURE_WIDTH, TEXTURE_HEIGHT, 0, GL_RGB, GL_FLOAT, texturePixels);
GLuint vbo;
glGenBuffers(1, &vbo);
// Create an element array
GLuint ebo;
glGenBuffers(1, &ebo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(screen2DVertices), screen2DVertices, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(screen2DIndices), screen2DIndices, GL_STATIC_DRAW);
// Specify the layout of the vertex data
GLint posAttrib = glGetAttribLocation(screenShader.Program, "position");
glEnableVertexAttribArray(posAttrib);
glVertexAttribPointer(posAttrib, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), (void*)0);
GLint texAttrib = glGetAttribLocation(screenShader.Program, "texcoord");
glEnableVertexAttribArray(texAttrib);
glVertexAttribPointer(texAttrib, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), (void*)(3 * sizeof(GLfloat)));
while (!glfwWindowShouldClose(window))
{
glfwPollEvents();
glClearColor(0.5f, 0.5f, 0.5f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
screenShader.Use();
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, (void*)0);
glfwSwapBuffers(window);
}Shaders:
//---------------------------Vertex Shader------------------------------------------
#version 330 core
in vec3 position;
in vec2 texcoord;
out vec2 Texcoord;
void main()
{
Texcoord = texcoord;
gl_Position = vec4(position, 1.0);
}
//---------------------------Fragment Shader------------------------------------------
#version 330 core
in vec2 Texcoord;
out vec4 outColour;
uniform sampler2D tex;
void main()
{
outColour = texture(tex, Texcoord) * vec4(1.0f);
}
