Object rendering strangely after adding transformations

Question

I'm adding transformations to my C OpenGL program. I'm using CGLM as my maths library. The program has no warnings or errors. Still however, when I compile and run the program, I get a distorted version of my intended image (it was not distorted before adding transformations).

The following is my program's main loop:

// Initialize variables for framerate counting
double lastTime = glfwGetTime();
int frameCount = 0;

// Program loop
while (!glfwWindowShouldClose(window)) {
    // Calculate framerate
    double thisTime = glfwGetTime();
    frameCount++;

    // If a second has passed.
    if (thisTime - lastTime >= 1.0) {
        printf("%i FPS\n", frameCount);

        frameCount = 0;
        lastTime = thisTime;
    }

    processInput(window);

    // Clear the window
    glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);
        
    // Bind textures on texture units
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, texture);
    glActiveTexture(GL_TEXTURE1);
    glBindTexture(GL_TEXTURE_2D, texture2);

    // Create transformations
    mat4 transform = {{1.0f}};
    glm_mat4_identity(transform);

    glm_translate(transform, (vec3){0.5f, -0.5f, 0.0f});
    glm_rotate(transform, (float)glfwGetTime(), (vec3){0.0f, 0.0f, 1.0f});

    // Get matrix's uniform location and set matrix
    shaderUse(myShaderPtr);
    GLint transformLoc = glGetUniformLocation(myShaderPtr->shaderID, "transform");
    // mat4 transform;
    glUniformMatrix4fv(transformLoc, 1, GL_FALSE, (float*)transform);

    glBindVertexArray(VAO);
    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

    glfwSwapBuffers(window); // Swap the front and back buffers
    glfwPollEvents(); // Check for events (mouse movement, mouse click, keyboard press, keyboard release etc.)
}

The Program is up on github here if you'd like to check out the full code.

The Output of the program is this (The square also rotates):

However, the intended output of the program is the penguin at 20% opacity on top and the box at 100% opacity underneath the penguin.

Answer 1

In the vertex shader, the location of the texture coordinate is 1:

#version 330 core

layout (location = 0) in vec3 aPos;
layout (location = 1) in vec2 aTexCoord;

However, when you specify the vertices, location 1 is used for the color attribute and position 2 for the text coordinates:

// Colour attribute
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
glEnableVertexAttribArray(1);

// Texture coord attribute
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
glEnableVertexAttribArray(2);

Remove the color attribute and use location 1 for the texture coordinates. e.g.:

// Texture coord attribute
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
glEnableVertexAttribArray(1);