I have created a simple 2D area using OpenGL, comprised of tiles. These tiles have been stretched relative to the screen's aspect ratio by default. To fix this I have attempted to use an orthographic projection matrix. Here is how I created it:
public void createProjectionMatrix() {
float left = 0;
float right = DisplayManager.getScreenWidth();
float top = 0;
float bottom = DisplayManager.getScreenHeight();
float near = 1;
float far = -1;
projectionMatrix.m00 = 2 / (r - l);
projectionMatrix.m11 = 2 / (t - b);
projectionMatrix.m22 = -2 / (f - n);
projectionMatrix.m30 = - (r + l) / (r - l);
projectionMatrix.m31 = - (t + b) / (t - b);
projectionMatrix.m32 = - (f + n) / (f - n);
projectionMatrix.m33 = 1;
}
The problem probably lies here but I just can't find it. I then call this method with the creation of my renderer, store it in a uniform variable and use it in the vertex shader like so:
vec4 worldPosition = transformationMatrix * vec4(position, 0, 1);
gl_Position = projectionMatrix * viewMatrix * worldPosition;
Where projectionMatrix is a mat4 which corresponds to the previously created orthographic projection matrix.
Right now absolutely nothing except for the clear color renders.
EDIT:
The orthographic projection matrix is created and loaded into the shaders right after the renderer's creation and after the shader's creation.
public Renderer() {
createOrthoMatrix();
terrainShader.start();
terrainShader.loadProjectionMatrix(projectionMatrix);
terrainShader.stop();
GL11.glEnable(GL13.GL_MULTISAMPLE);
GL11.glClearColor(0, 0, 0.5f, 1);
}
The rest of the matrices are passed in at each render with the loadUniforms() method.
for(Terrain t : batch) {
loadUniforms(t, terrainManager, camera, lights);
GL11.glDrawElements(GL11.GL_TRIANGLES, model.getModel().getVertexCount(), GL11.GL_UNSIGNED_INT, 0);
}
private void loadUniforms(Terrain t, TerrainManager tm, Camera camera, List<Light> lights) {
Matrix4f matrix = Maths.createTransformationMatrix(t.getPosition(), 0, 0, 0, 1);
terrainShader.loadTransformationMatrix(matrix);
terrainShader.loadViewMatrix(camera);
terrainShader.loadNumberOfRows(tm.getNumberOfRows());
terrainShader.loadOffset(t.getOffset());
terrainShader.loadLights(lights);
}
Finally this is what the vertex shader looks like:
#version 400 core
in vec2 position;
uniform mat4 transformationMatrix;
uniform mat4 viewMatrix;
uniform mat4 projectionMatrix;
void main(void) {
vec4 worldPosition = transformationMatrix * vec4(position, 0, 1);
gl_Position = projectionMatrix * viewMatrix * worldPosition;
}
It has been a long and arduous task (if I may sound incompetent myself). But I have found a solution to my problem, there is probably a better way to solve it, but this is how I did it.
I changed the createProjectionMatrix() to look like
Multiplying m00 and m11 by a large number is the only way I am able to see anything besides the clear color. If I remember this correctly, it is because the renderer is rendering at less than a pixel. This idea was presented to me by @NicoSchertler. So thank you very much! The shaders looks the same and now it runs well. If anyone has a less bootleg solution please share it, as I will be glad to see how it was solved. Here is a link that was very helpful to me, OpenGL 3+ with orthographic projection of directional light.