OpenGL 3.2 trouble setting up matrices - c++

Question

I am using GLM to manage my matrices, but I am running in to some problems that make no sense to me. When I set the projection matrix to anything other than an identity matrix, I can't see the square I am trying to draw. If it is an identity it will work. Something similiar happens with my view matrix. If I try and translate past -1 or +1 the square will dissapear, otherwise it seems to have no effects.
There are no OpenGL errors, GLSL linker/compiler errors, and glGetUniformLocation returns a valid location. Also the shader program is correctly being used.
Also I have tested the shader to see if it is getting the correct values passed to each of the matrices (by changing the color of the square if the value is correct).
Here's how I set up the projection matrix:
projectionMatrix = glm::perspective(60.0f, (float)windowWidth / (float)windowHeight, 0.1f, 100.0f);
And here's my draw function:
void OpenGLContext::render(void) {
glViewport(0, 0, windowWidth, windowHeight); // Set the viewport size to fill the window
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT); // Clear required buffers
//Set up matrices
viewMatrix = glm::translate(glm::mat4(1.0f), glm::vec3(0.0f, 0.0f, -5.0f));
modelMatrix = glm::scale(glm::mat4(1.0f), glm::vec3(.5f));
shader->bind();
int projectionMatrixLocation = glGetUniformLocation(shader->id(), "projectionMatrix");
int viewMatrixLocation = glGetUniformLocation(shader->id(), "viewMatrix");
int modelMatrixLocation = glGetUniformLocation(shader->id(), "modelMatrix");
glUniformMatrix4fv(projectionMatrixLocation, 1, GL_FALSE, &projectionMatrix[0][0]);
glUniformMatrix4fv(viewMatrixLocation, 1, GL_FALSE, &viewMatrix[0][0]);
glUniformMatrix4fv(modelMatrixLocation, 1, GL_FALSE, &modelMatrix[0][0]);
glBindVertexArray(vaoID[0]);
glDrawArrays(GL_TRIANGLES, 0, 6);
glBindVertexArray(0);
shader->unbind();
SwapBuffers(hdc);
}
Here's the shader.vert
#version 150 core
uniform mat4 projectionMatrix;
uniform mat4 viewMatrix;
uniform mat4 modelMatrix;
in vec3 in_Position;
in vec3 in_Color;
out vec3 pass_Color;
void main(void)
{
gl_Position = projectionMatrix * viewMatrix * modelMatrix * vec4(in_Position, 1.0);
pass_Color = in_Color;
}
Here's shader.frag
#version 150 core
uniform mat4 projectionMatrix;
uniform mat4 viewMatrix;
uniform mat4 modelMatrix;
in vec3 pass_Color;
out vec4 out_Color;
void main(void)
{
out_Color = vec4(pass_Color, 1.0);
}
Sorry forgot about what i'm drawing:
void OpenGLContext::createSquare(void)
{
float* vertices = new float[18];
vertices[0] = -0.5; vertices[1] = -0.5; vertices[2] = 0.0; // Bottom left corner
vertices[3] = -0.5; vertices[4] = 0.5; vertices[5] = 0.0; // Top left corner
vertices[6] = 0.5; vertices[7] = 0.5; vertices[8] = 0.0; // Top Right corner
vertices[9] = 0.5; vertices[10] = -0.5; vertices[11] = 0.0; // Bottom right corner
vertices[12] = -0.5; vertices[13] = -0.5; vertices[14] = 0.0; // Bottom left corner
vertices[15] = 0.5; vertices[16] = 0.5; vertices[17] = 0.0; // Top Right corner
glGenVertexArrays(1, &vaoID[0]);
glBindVertexArray(vaoID[0]);
glGenBuffers(1, vboID);
glBindBuffer(GL_ARRAY_BUFFER, vboID[0]);
glBufferData(GL_ARRAY_BUFFER, 18 * sizeof(GLfloat), vertices, GL_STATIC_DRAW);
glVertexAttribPointer((GLuint) 0, 3, GL_FLOAT, GL_FALSE, 0, 0);
glEnableVertexAttribArray(0); // Disable our Vertex Array Object
glBindVertexArray(0);
delete [] vertices;
}
Setting my matrices like this results in nothing being drawn on the screen. Like I said if I set the projection and view matrices to an identity it will work. The scaling on the modelMatrix seems to always work as well.

Answer 1

There is no attribute on position 1 (in_Color). If you just left it out of this question, then the problem are the locations, which you are not defining in the shaders. I've never actually tested it without the location part, but I think it's necessary, at least for multiple values: you should use e.g. layout(location = 0) in in_Position.