Abnormal Texturing?

Newbie & Debugging Questions
#1

Hi. So I’m trying out OpenGL 3.3 with Core Profile and I’m having some weird results when drawing textures to triangles.

Here’s what the result looks like:

The problem: I’m not expecting that to be drawn. I have a plain pink texture (255, 0, 255, 255) that should be drawn on the triangle. There is some transparency issues too.

Here’s my main render loop:


protected void renderScene(Renderer renderer) {
	viewMatrix.rotateX(xRot);
	viewMatrix.rotateY(yRot);
	viewMatrix.translate(new Vector3f(pos).negate());

	basicShader.bind();

	glActiveTexture(GL_TEXTURE0);
	texture.bind();
	basicShader.setUniform("tex", 0);

	basicShader.setUniform("modelMatrix", modelMatrix);
	basicShader.setUniform("viewMatrix", viewMatrix);
	basicShader.setUniform("projectionMatrix", projectionMatrix);

	Tessellator t = Tessellator.instance;
	t.begin(GL_TRIANGLES);
	t.colour(1, 1, 0, 1);
	t.normal(0, -2, 0);

	t.texCoord(1.0f, 1.0f);
	t.vertex(1.0f, 1.0f, 0.0f);

	t.texCoord(0.0f, 1.0f);
	t.vertex(-1.0f, 1.0f, 0.0f);

	t.texCoord(1.0f, 0.0f);
	t.vertex(1.0f, -1.0f, 0.0f);

	t.texCoord(0.0f, 0.0f);
	t.vertex(-1.0f, -1.0f, 0.0f);
	t.end();

	texture.unbind();

	basicShader.unbind();
}

Note: The Tessellator class is basically a helpful vertex drawing tool where I use Vertex Array Objects to draw my vertices.

Here’s my fragment shader code:


#version 330 core

in vec4 vColour;
in vec2 vTexCoords;

out vec4 fragColour;

uniform sampler2D tex;

void main() {
	vec4 colour = vColour*texture(tex, vTexCoords);
    fragColour = colour;
}

Edit: Here’s my Texture loading code, sorry.


public Texture(int width, int height, int[] pixels) {
	this.width = width;
	this.height = height;
	this.pixels = pixels;
}

public void create(ParameterListener parameterListener) {
	ByteBuffer buffer = MemoryTracker.createByteBuffer(width * height * 4);
	for (int y = 0; y < height; y++) {
		for (int x = 0; x < width; x++) {
			int colour = pixels[x + y * width];

			byte r = (byte) ((colour >> 16) & 0xff);
			byte g = (byte) ((colour >> 8) & 0xff);
			byte b = (byte) (colour & 0xff);
			byte a = (byte) ((colour >> 24) & 0xff);
			buffer.put(r).put(g).put(b).put(a);
		}
	}

	id = glGenTextures();
	glBindTexture(GL_TEXTURE_2D, id);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, buffer);

	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST/*GL_LINEAR*/);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

	glBindTexture(GL_TEXTURE_2D, 0);

	System.out.println("Successfully created texture!");
}

If you need anything else to help me please ask. Thanks for your time. :slight_smile:

#2

And the problem…? What are you expecting to get?

#3

I’m not expecting that to be drawn. I have a plain pink texture (255, 0, 255) that should be drawn on the triangle.

#4

Try to

  1. not use your tessellator. Just draw a GL_QUADS quad to ensure that’s not the problem.
  2. show us the texture loading code.
#5

Hi, thanks for your time. I’ve updated the post with the texture loading code.

I’m not sure what you mean by not use the Tessellator? It’s a class that has worked before in my other projects that have used textures. And I don’t think you can use GL_QUADS with VBO’s. I can’t use Immediate Mode either because it’s depreciated.

#6

You didn’t flip your buffer. You’re uploading garbage.

#7

I completely forgot about that. Thank you. Sorry for wasting your time.

#8

You did not waste anyone’s time (probably), because if someone comes along and has the same problem, they can try this potential solution. :point:

Edit: Plus, now it will be more likely for you to remember to flip you buffers!

#9

No need to apologize.