Hey folks,

Seeing some odd behaviour with a very simple OpenGL shader I'm trying to get working.

Here's the vertex shader:

#version 400

////////////////////
// Input Variables
////////////////////

in vec3 inputPosition;
in vec3 inputColor;


////////////////////
// Output Variables
////////////////////

out vec3 outputColor;


////////////////////
// Uniform Variables
////////////////////

uniform mat4 worldMatrix;
uniform mat4 viewMatrix;
uniform mat4 projectionMatrix;


////////////////////
// Vertex Shader
////////////////////

void main( void )
{
	// calculate the position of the vertex using world/view/projection matrices
	gl_Position = worldMatrix * vec4( inputPosition, 1.0f );
	gl_Position = viewMatrix * gl_Position;
	gl_Position = projectionMatrix * gl_Position;
	
	// store the input colour for the fragment shader
	outputColor = vec3( 1.0f, 1.0f, 1.0f );//inputColor;
}

And this is the fragment shader:

#version 400

////////////////////
// Input Variables
////////////////////

in vec3 inputColor;


////////////////////
// Output Variables
////////////////////

out vec4 outputColor;


////////////////////
// Fragment Shader
////////////////////

void main( void )
{
	outputColor = vec4( inputColor, 1.0f );//vec4( 1.0f, 1.0f, 1.0f, 1.0f);
}

If I try and use the 'inputColor' in the fragment shader everything is just rendered black... however if I explicitly set the colour (in the commented out code) everything renders correctly... so there's a breakdown in communication between my vertex and fragment shaders.

Is there anything obvious I'm missing in the shader code? I'm not seeing any compilation warnings from the C++ code side of things, and all of the world/view/projection matrices are being passed in correctly.

Thanks!

I had a quick look at the fragment shader using NSight, and while the vertex shader looks like it has valid input parameters, I couldn't see anything relating to color in the fragment shader.

I've attached a couple of screen-caps from NSight.

6 hours ago, _Silence_ said:

Your 'out' variables in your vertex shaders must match the 'in' variables in your fragment shaders.

Oh damn, thanks for that!

I assumed that OpenGL would map the 'out' variable from the vertex shader to the 'in' variable of the fragment shader - assuming the types matched; had no idea the actual variable names had to be the same. Thank you, this was driving me a bit insane!