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C++ Shader help

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Hello Everyone,

I am having an issue getting my shaders to work. Here is what I have. This is the rendering function.

glUseProgram( program_id );

GLfloat v[6] = { 0.0f , 0.0f , 1.0f , 1.0f , 1.0f, 0.0f };
GLuint vbo_id = 0;
glGenBuffers( 1 , &vbo_id);
glBindBuffer( GL_ARRAY_BUFFER , vbo_id);
glBufferData( GL_ARRAY_BUFFER , sizeof(v) , v , GL_STATIC_DRAW);

glEnableVertexAttribArray( 0 );
glBindBuffer( GL_ARRAY_BUFFER , vbo_id );

glVertexAttribPointer( 0 , 2 , GL_FLOAT, GL_FALSE , 0 , 0 );
glDrawArrays( GL_TRIANGLES , 0 , 3 );

glBindBuffer( GL_ARRAY_BUFFER , 0 );

And the vertex shader

#version 330

in vec2 vertex_position;
//layout( location = 0 ) in vec2 vertex_position;
void main(){
	gl_Position.xy = vertex_position * 1.2;
	gl_Position.z = 0;
	gl_Position.w = 1;

The fragment shader

#version 330

void main(){
	gl_FragColor = vec4(1.0,0.0,0.0,1.0);


I did not post the compiling , linking and attribute adding code because it appears to work. For example, if I make a syntax error in one the shaders, it get a warning. Or if there's a linker problem for example.

My issue is that I do get a triangle to show up on the screen, but no matter what I do to the vertex or fragment shaders (for example changing the color or size ) it has no effect with what I see on the screen.

In essence, there appears to be no communication between the shaders and glew.

My frustration is further compounded by the fact that I was able to get this working before on the same laptop.

If anyone has any ideas on what could be wrong with my incredibly simple program, please let me know.





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