CODEWITHSUNDEEP
androidopengl-esopengl-es-2.0
user2426316
user2426316

Reputation: 7331

How can I change the color of a line loop in OpenGL?

I am drawing a simple rectangular line loop using this call:

GLES20.glDrawElements(GLES20.GL_LINE_LOOP,
                    numIndices, GLES20.GL_UNSIGNED_SHORT,
                    getIndicesBuffer());

Now, the color of this line loop is black. How can I change it to another color? Red, for example.

Upvotes: 0

Views: 1221

Answers (1)

ratchet freak
ratchet freak

Reputation: 48196

You will need to change your fragment shader, I am going to assume you want to change the color per line loop.

change your fragment shader to this:

uniform vec4 color;

main(){
    gl_FragColor = color;
}

And before each glDrawElements you can then call GLES20.glUniform4f(colorLoc, r, g, b, a);. Where colorLoc is the return value of GLES20.glGetUniformLocation(program, "color"); and r, g, b and A are the red, green, blue and alpha values in the range 0-1 of the color you want.

Upvotes: 2

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