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I'm currently learning modern OpenGL. So far I have been programming everything within the same scope of the primary cpp file, but the more I learn, the more that file becomes very lengthy and cluttered. So naturally, I have been trying to break up my code by putting some within a user defined function and even a user defined class, but I keep having the same problem in that I just have a black screen instead of a rendered triangle.

 

I am currently using Glfw3 and Glew with my code if that helps. I have also tried passing certain values, like window handles, but to no avail. If I put all the code within my user defined function in main(), the triangle becomes rendered.

 

 

Here is my code:

 

framework.h

#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <iostream>
#include <fstream>

#pragma comment(lib, "glfw3dll.lib")
#pragma comment(lib, "glew32.lib")
#pragma comment(lib, "opengl32.lib")

using namespace std;

framework.cpp

#include "framework.h"
#include "rendering.h"


int windowWidth = 800;
int windowHeight = 450;
ofstream outFile("output.txt");
renderingUtils renderingClass; //Rendering Utils Class
void renderFunction(float*, GLFWwindow*);

float triangleW = 0.125;
float triangleH = 0.125;
float coordinateX = 0.25;
float coordinateY = 0.25;
float points[24] = {
	0.0f, 0.0f, 0.0f, 1.0f,
	0.5f, 0.0f, 0.0f, 1.0f,
	0.0f, 0.5f, 0.0f, 1.0f,
	1.0f, 0.0f, 0.0f, 1.0f,
	0.0f, 1.0f, 0.0f, 1.0f,
	0.0f, 0.0f, 1.0f, 1.0f,
};
/*float points[24] = {  //Vertex Information
	coordinateX, coordinateY, 0.0f, 1.0f,
	coordinateX + triangleW, coordinateY, 0.0f, 1.0f,
	coordinateX + (triangleW / 2), coordinateY + triangleH, 0.0f, 1.0f, //First Triangle
	1.0f, 0.0f, 0.0f, 1.0f,
	0.0f, 1.0f, 0.0f, 1.0f,
	0.0f, 0.0f, 1.0f, 1.0f, //Color Information
};*/

int main(){

	//Start GL context O/S window using the GLFW helper library
	if (!glfwInit()){
		outFile << "ERROR: Could not start GLFW3\n";
		return 1;
	}

	GLFWwindow* window = glfwCreateWindow(windowWidth, windowHeight, "Tutorial Project", NULL, NULL);
	if (!window){
		outFile << "ERROR: Could not open window with GLFW3\n";
		glfwTerminate();
		return 1;
	}

	glfwMakeContextCurrent(window);

	//start GLEW extension handler
	glewExperimental = GL_TRUE;
	glewInit();

	//Get version info
	const GLubyte* renderer = glGetString(GL_RENDERER); //Get renderer string
	const GLubyte* version = glGetString(GL_VERSION); //Version as a string

	std::cout << "Renderer: " << renderer << "\n";
	std::cout << "OpenGL version supported: " << version << "\n";



	//Initialize Display
	renderFunction(points, window);



	
	while (!glfwWindowShouldClose(window)){
		//Compute Position Offsets
		//Adjust Vertex Data
		//Render Display
		//renderingClass.updateScene();





		//Update other events like input handling
		glfwPollEvents();

	}
	
	//Close GL context and any other GLFW resources
	glfwTerminate();
	getchar();
	return 0;

}

void renderFunction(float* points, GLFWwindow* window){
	glfwMakeContextCurrent(window);

	// Test Code below
	unsigned int vbo = 0;
	unsigned int vao = 0;
	unsigned int vs;
	unsigned int fs;
	unsigned int program;
	const char* vertex_shader =
		"#version 330\n"
		"layout(location = 0) in vec4 position;"
		"layout(location = 1) in vec4 color;"
		"smooth out vec4 theColor;"
		"void main () {"
		"  gl_Position = position;"
		"  theColor = color;"
		"}";
	const char* fragment_shader =
		"#version 330\n"
		"smooth in vec4 theColor;"
		"out vec4 outputColor;"
		"void main () {"
		"  outputColor = theColor;"
		"}";
	std::cout << "Scene set up.\n";
	std::cout << points[4] << "\n";
	//Tell GL to only draw onto a pixel if the shape is closer to the viewer
	glEnable(GL_DEPTH_TEST); //Enable Depth-Testing
	glDepthFunc(GL_LESS); //Depth-testing interprests a smaller value as "closer"
	glViewport(0, 0, (GLsizei)800, (GLsizei)450);

	glGenBuffers(1, &vbo); //
	glBindBuffer(GL_ARRAY_BUFFER, vbo); //
	glBufferData(GL_ARRAY_BUFFER, sizeof(points), points, GL_STATIC_DRAW); //
	glBindBuffer(GL_ARRAY_BUFFER, 0);

	glGenVertexArrays(1, &vao); //
	glBindVertexArray(vao); //
	glBindBuffer(GL_ARRAY_BUFFER, vbo);
	glEnableVertexAttribArray(0); //
	glEnableVertexAttribArray(1); //

	glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 0, 0); //
	glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, 0, (void*)48); //


	vs = glCreateShader(GL_VERTEX_SHADER);//
	glShaderSource(vs, 1, &vertex_shader, NULL); //
	glCompileShader(vs); //

	GLint status;
	glGetShaderiv(vs, GL_COMPILE_STATUS, &status);
	if (status == GL_FALSE) { std::cout << "Compile status1: fail\n"; }
	fs = glCreateShader(GL_FRAGMENT_SHADER); //
	glShaderSource(fs, 1, &fragment_shader, NULL); //
	glCompileShader(fs); //
	GLint status2;
	glGetShaderiv(fs, GL_COMPILE_STATUS, &status2);
	if (status2 == GL_FALSE){ std::cout << "Compile status2: fail\n"; }

	program = glCreateProgram(); //
	glAttachShader(program, fs); //
	glAttachShader(program, vs); //
	glLinkProgram(program); //
	GLint status3;
	glGetProgramiv(program, GL_LINK_STATUS, &status3);
	if (status3 == GL_FALSE) { std::cout << "GL program failure \n"; }

	glClearColor(0.0f, 0.0f, 0.0f, 0.0f); //
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); //

	glUseProgram(program); //
	glBindVertexArray(vao); //
	glDrawArrays(GL_TRIANGLES, 0, 3); //

	glfwSwapBuffers(window);
}

Any ideas as why this is not working?

Edited by jccourtney

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Oe problem, at least, is your glBufferData call where you use sizeof(points). The variable points is a pointer, thus sizeof(points) is the size of the pointer. You are thus loading a buffer with, most likely, either 4 of 8 bytes of data. If you want the size of the original points array that you pass to renderFunction, you need to pass its size to the function, because once the array decays into the pointer at the call site, the size information is lost.

 

But, that aside, do not create and upload data in a render function. Make it a separate init function, and have the render function refer to the buffer objects instead.

Edited by Brother Bob

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Brother Bob, 

 

I corrected that and also adjust my code to your suggestion, but unfortunately I'm still just getting a black screen. 

 

Here's my updated framework.cpp file:

#include "framework.h"

int windowWidth = 800;
int windowHeight = 450;
ofstream outFile("output.txt");
void renderFunction(float*, GLFWwindow*, GLuint*, GLuint*, GLuint*, GLuint*, GLuint*);
void initRenderer(float*, GLFWwindow*, GLuint*, GLuint*, GLuint*, GLuint*, GLuint*);
float triangleW = 0.125;
float triangleH = 0.125;
float coordinateX = 0.25;
float coordinateY = 0.25;
float points[24] = {
	0.0f, 0.0f, 0.0f, 1.0f,
	0.5f, 0.0f, 0.0f, 1.0f,
	0.0f, 0.5f, 0.0f, 1.0f,
	1.0f, 0.0f, 0.0f, 1.0f,
	0.0f, 1.0f, 0.0f, 1.0f,
	0.0f, 0.0f, 1.0f, 1.0f,
};
GLuint vbo = 0;
GLuint vao = 0;
GLuint vs;
GLuint fs;
GLuint program;

int main(){

	//Start GL context O/S window using the GLFW helper library
	if (!glfwInit()){
		outFile << "ERROR: Could not start GLFW3\n";
		return 1;
	}

	GLFWwindow* window = glfwCreateWindow(windowWidth, windowHeight, "Tutorial Project", NULL, NULL);
	if (!window){
		outFile << "ERROR: Could not open window with GLFW3\n";
		glfwTerminate();
		return 1;
	}
	
	glfwMakeContextCurrent(window);

	//start GLEW extension handler
	glewExperimental = GL_TRUE;
	glewInit();

	//Get version info
	const GLubyte* renderer = glGetString(GL_RENDERER); //Get renderer string
	const GLubyte* version = glGetString(GL_VERSION); //Version as a string

	std::cout << "Renderer: " << renderer << "\n";
	std::cout << "OpenGL version supported: " << version << "\n";



	//Initialize Display
	initRenderer(points, window, &vbo, &vao, &vs, &fs, &program);



	
	while (!glfwWindowShouldClose(window)){
		//Compute Position Offsets
		//Adjust Vertex Data
		//Render Display
		//renderingClass.updateScene();
		renderFunction(points, window, &vbo, &vao, &vs, &fs, &program);




		//Update other events like input handling
		glfwPollEvents();

	}
	
	//Close GL context and any other GLFW resources
	glfwTerminate();
	getchar();
	return 0;

}

void renderFunction(float* points, GLFWwindow* window, GLuint* vbo, GLuint* vao, GLuint* vs, GLuint* fs, GLuint* program){
	glfwMakeContextCurrent(window);
	glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
	glClear(GL_COLOR_BUFFER_BIT);
	glUseProgram(*program);
	glBindBuffer(GL_ARRAY_BUFFER, *vbo);
	glEnableVertexAttribArray(0);
	glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 0, 0);
	glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, 0, (void*)48);

	glDrawArrays(GL_TRIANGLES, 0, 3);

	glDisableVertexAttribArray(0);
	glUseProgram(0);

	glfwSwapBuffers(window);

}

void initRenderer(float* points, GLFWwindow* window, GLuint* vbo, GLuint* vao, GLuint* vs, GLuint* fs, GLuint* program){
	glfwMakeContextCurrent(window);
	const char* vertex_shader =
		"#version 330\n"
		"layout(location = 0) in vec4 position;"
		"layout(location = 1) in vec4 color;"
		"smooth out vec4 theColor;"
		"void main () {"
		"  gl_Position = position;"
		"  theColor = color;"
		//vec4 (vp, 1.0);"
		"}";
	const char* fragment_shader =
		"#version 330\n"
		"smooth in vec4 theColor;"
		"out vec4 outputColor;"
		"void main () {"
		"  outputColor = theColor;"
		"}";

	//Tell GL to only draw onto a pixel if the shape is closer to the viewer
	glEnable(GL_DEPTH_TEST); //Enable Depth-Testing
	glDepthFunc(GL_LESS); //Depth-testing interprests a smaller value as "closer"
	glViewport(0, 0, (GLsizei)800, (GLsizei)450);

	glGenBuffers(1, vbo); 
	glBindBuffer(GL_ARRAY_BUFFER, *vbo); 
	glBufferData(GL_ARRAY_BUFFER, sizeof(points), points, GL_STATIC_DRAW); //
	glBindBuffer(GL_ARRAY_BUFFER, 0);

	glGenVertexArrays(1, vao);
	glBindVertexArray(*vao);
	glBindBuffer(GL_ARRAY_BUFFER, *vbo);
	glEnableVertexAttribArray(0); 
	glEnableVertexAttribArray(1); 

	glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 0, 0); 
	glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, 0, (void*)48); 


	*vs = glCreateShader(GL_VERTEX_SHADER);
	glShaderSource(*vs, 1, &vertex_shader, NULL); 
	glCompileShader(*vs); //

	GLint status;
	glGetShaderiv(*vs, GL_COMPILE_STATUS, &status);
	if (status == GL_FALSE) { std::cout << "Compile status1: fail\n"; }
	*fs = glCreateShader(GL_FRAGMENT_SHADER); //
	glShaderSource(*fs, 1, &fragment_shader, NULL); //
	glCompileShader(*fs); //
	
	GLint status2;
	glGetShaderiv(*fs, GL_COMPILE_STATUS, &status2);
	if (status2 == GL_FALSE){ std::cout << "Compile status2: fail\n"; }

	*program = glCreateProgram(); //
	glAttachShader(*program, *fs); //
	glAttachShader(*program, *vs); //
	glLinkProgram(*program); //
	GLint status3;
	glGetProgramiv(*program, GL_LINK_STATUS, &status3);
	if (status3 == GL_FALSE) { std::cout << "GL program failure \n"; }
}
Edited by jccourtney

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I'm currently learning modern OpenGL. So far I have been programming everything within the same scope of the primary cpp file, but the more I learn, the more that file becomes very lengthy and cluttered. So naturally, I have been trying to break up my code by putting some within a user defined function and even a user defined class, but I keep having the same problem in that I just have a black screen instead of a rendered triangle.

 

Sorry, I don't have a specific answer to your question. You have the experienced the black screen of death in OpenGL. There are quite a lot of single point of failures when programming OpenGL, and many of them will give you a black screen.

 

My personal experience is to do as follows:

  1. Whenever something works, I check it in to a version control.
  2. I make many small check ins, making it easy to back step when something stops working.
  3. I make sure every small step still works.

This relates not only to OpenGL, of course. Now and then, I grow more confident as I feel I have enough experience. And then I suddenly have to spend a lot of time debugging and try to understand why something was broken.

 

Otherwise, I would say you are on the right path. That is, you need to create a library/framework for using OpenGL (or use a library from someone else). OpenGL is low level programming, and it has helped me to add some layers above it.

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You didn't correct the error I mentioned. In initRenderer, you are still taking the size of the pointer in the call to glBufferData, not the size of the original array data; points is still a pointer, and sizeof(points) still returns the size of the pointer which is likely either 4 or 8 bytes. You need to pass the size of the array data to initRenderer, because it cannot know the size of the original array by the pointer alone.

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You didn't correct the error I mentioned. In initRenderer, you are still taking the size of the pointer in the call to glBufferData, not the size of the original array data; points is still a pointer, and sizeof(points) still returns the size of the pointer which is likely either 4 or 8 bytes. You need to pass the size of the array data to initRenderer, because it cannot know the size of the original array by the pointer alone.

Brother Bob, I updated the code to include the hard coded value of the array length and sizeof(float) in the glBufferData call. I also changed the prototype and declaration sections to use float points[] instead of float* points.



#include "framework.h"

int windowWidth = 800;
int windowHeight = 450;
ofstream outFile("output.txt");
void renderFunction(float[], GLFWwindow*, GLuint*, GLuint*, GLuint*, GLuint*, GLuint*);
void initRenderer(float[], GLFWwindow*, GLuint*, GLuint*, GLuint*, GLuint*, GLuint*);
float triangleW = 0.125;
float triangleH = 0.125;
float coordinateX = 0.25;
float coordinateY = 0.25;
float points[24] = {
	0.0f, 0.0f, 0.0f, 1.0f,
	0.5f, 0.0f, 0.0f, 1.0f,
	0.0f, 0.5f, 0.0f, 1.0f,
	1.0f, 0.0f, 0.0f, 1.0f,
	0.0f, 1.0f, 0.0f, 1.0f,
	0.0f, 0.0f, 1.0f, 1.0f,
};
GLuint vbo = 0;
GLuint vao = 0;
GLuint vs;
GLuint fs;
GLuint program;



/*float points[24] = {  //Vertex Information
	coordinateX, coordinateY, 0.0f, 1.0f,
	coordinateX + triangleW, coordinateY, 0.0f, 1.0f,
	coordinateX + (triangleW / 2), coordinateY + triangleH, 0.0f, 1.0f, //First Triangle
	1.0f, 0.0f, 0.0f, 1.0f,
	0.0f, 1.0f, 0.0f, 1.0f,
	0.0f, 0.0f, 1.0f, 1.0f, //Color Information
};*/

int main(){
	//Start GL context O/S window using the GLFW helper library
	if (!glfwInit()){
		outFile << "ERROR: Could not start GLFW3\n";
		return 1;
	}

	GLFWwindow* window = glfwCreateWindow(windowWidth, windowHeight, "Tutorial Project", NULL, NULL);
	if (!window){
		outFile << "ERROR: Could not open window with GLFW3\n";
		glfwTerminate();
		return 1;
	}
	
	glfwMakeContextCurrent(window);

	//start GLEW extension handler
	glewExperimental = GL_TRUE;
	glewInit();

	//Get version info
	const GLubyte* renderer = glGetString(GL_RENDERER); //Get renderer string
	const GLubyte* version = glGetString(GL_VERSION); //Version as a string

	std::cout << "Renderer: " << renderer << "\n";
	std::cout << "OpenGL version supported: " << version << "\n";



	//Initialize Display
	initRenderer(points, window, &vbo, &vao, &vs, &fs, &program);



	
	while (!glfwWindowShouldClose(window)){

		renderFunction(points, window, &vbo, &vao, &vs, &fs, &program);




		//Update other events like input handling
		glfwPollEvents();

	}
	
	//Close GL context and any other GLFW resources
	glfwTerminate();
	getchar();
	return 0;

}

void renderFunction(float points[], GLFWwindow* window, GLuint* vbo, GLuint* vao, GLuint* vs, GLuint* fs, GLuint* program){
	glfwMakeContextCurrent(window);
	glClearColor(0.0f, 0.0f, 0.3f, 0.0f);
	glClear(GL_COLOR_BUFFER_BIT);
	glUseProgram(*program);
	glBindBuffer(GL_ARRAY_BUFFER, *vbo);
	glEnableVertexAttribArray(0);
	glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 0, 0);
	glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, 0, (void*)48);

	glDrawArrays(GL_TRIANGLES, 0, 3);

	glDisableVertexAttribArray(0);
	glUseProgram(0);

	glfwSwapBuffers(window);

}

void initRenderer(float points[], GLFWwindow* window, GLuint* vbo, GLuint* vao, GLuint* vs, GLuint* fs, GLuint* program){
	glfwMakeContextCurrent(window);
	const char* vertex_shader =
		"#version 330\n"
		"layout(location = 0) in vec4 position;"
		"layout(location = 1) in vec4 color;"
		"smooth out vec4 theColor;"
		"void main () {"
		"  gl_Position = position;"
		"  theColor = color;"
		"}";
	const char* fragment_shader =
		"#version 330\n"
		"smooth in vec4 theColor;"
		"out vec4 outputColor;"
		"void main () {"
		"  outputColor = theColor;"
		"}";

	//Tell GL to only draw onto a pixel if the shape is closer to the viewer
	glEnable(GL_DEPTH_TEST); //Enable Depth-Testing
	glDepthFunc(GL_LESS); //Depth-testing interprests a smaller value as "closer"
	glViewport(0, 0, (GLsizei)800, (GLsizei)450);

	glGenBuffers(1, vbo); 
	glBindBuffer(GL_ARRAY_BUFFER, *vbo); 
	glBufferData(GL_ARRAY_BUFFER, 24*sizeof(float), points, GL_STATIC_DRAW); //
	glBindBuffer(GL_ARRAY_BUFFER, 0);


	glGenVertexArrays(1, vao);
	glBindVertexArray(*vao);
	glBindBuffer(GL_ARRAY_BUFFER, *vao);
	glEnableVertexAttribArray(0); 
	glEnableVertexAttribArray(1); 

	glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 0, 0); 
	glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, 0, (void*)48); 


	*vs = glCreateShader(GL_VERTEX_SHADER);
	glShaderSource(*vs, 1, &vertex_shader, NULL); 
	glCompileShader(*vs); //

	GLint status;
	glGetShaderiv(*vs, GL_COMPILE_STATUS, &status);
	if (status == GL_FALSE) { std::cout << "Compile status1: fail\n"; }
	*fs = glCreateShader(GL_FRAGMENT_SHADER); //
	glShaderSource(*fs, 1, &fragment_shader, NULL); //
	glCompileShader(*fs); //
	
	GLint status2;
	glGetShaderiv(*fs, GL_COMPILE_STATUS, &status2);
	if (status2 == GL_FALSE){ std::cout << "Compile status2: fail\n"; }

	*program = glCreateProgram(); //
	glAttachShader(*program, *fs); //
	glAttachShader(*program, *vs); //
	glLinkProgram(*program); //
	GLint status3;
	glGetProgramiv(*program, GL_LINK_STATUS, &status3);
	if (status3 == GL_FALSE) { std::cout << "GL program failure \n"; }
}

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glBindBuffer(GL_ARRAY_BUFFER, *vao);

Here, in initRenderer (line 144) you're attempting to bind a VAO as a VBO. Try using *vbo there.

 

In your renderFunction it looks like you're rendering with the VBO but your VAO is still bound. Pick one or the other. If you want to render with the VBO directly (and this is preferred to VAOs anyway), then disable your VAO before calling your renderFunction.

 

Your clear color is also fully transparent. You probably want a 1.0f as the last component.

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Using the above code, I found that by simply deleting the lines below or even changing the second line to GL_ALWAYS,  I managed to produce a rendered triangle.

	glEnable(GL_DEPTH_TEST); //Enable Depth-Testing
	glDepthFunc(GL_LESS); //Depth-testing interprets a smaller value as "closer" 

Now the question is why? I checked my vertex data, which is the first half of the array points, and I used a z value of 0. Does anyone have any ideas?

 

UPDATE:

 

I changed line 96, while not implementing my findings as above, from

glClear(GL_COLOR_BUFFER_BIT);

to

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

and I was able to get a rendered triangle.

Edited by jccourtney

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glBindBuffer(GL_ARRAY_BUFFER, *vao);

Here, in initRenderer (line 144) you're attempting to bind a VAO as a VBO. Try using *vbo there.

 

In your renderFunction it looks like you're rendering with the VBO but your VAO is still bound. Pick one or the other. If you want to render with the VBO directly (and this is preferred to VAOs anyway), then disable your VAO before calling your renderFunction.

 

Your clear color is also fully transparent. You probably want a 1.0f as the last component.

 

Thanks! I'll go ahead and make those two changes with the glClearColor call and line 144. Can you explain a little more what you mean by rendering with the VBO directly? I've tried looking online for some more information, but so far I haven't found anything useful that doesn't include VAOs. 

 

 

My basic understanding for rendering (the loop, not the initial setup) is, assuming a static draw, the following:

...
glBindVertexArray(vertexArrayObject);
glBindBuffer(GL_ARRAY_BUFFER, vertexBufferObject1);

glEnableVertexAttribArray(0);


glBindBuffer(GL_ARRAY_BUFFER, vertexBufferObjectN); //Any remaining vbos that might contain color information, etc
glEnableVertexAttribArray(N); //For any additional indexes, such as if there were an additional one for color, etc
glVertexAttribPointer(N, 4, GL_FLOAT, GL_FALSE, 0, 0); //For any additional indexes and buffers

glUseProgram(program);
glDrawArrays(GL_TRIANGLES, 0, 3);

//Clean up functions to follow

Is anything incorrect or redundant here? Thanks!

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      I figure this is simpler and I don't plan on putting some sort of exorbitant fee for a monthly subscription or the like.
      I was thinking on the lines of a few dollars 1,2, and 3 and the larger subscription gets you assistance with the content in the tutorials if needed that month.
      Maybe another fee if it is related but not directly in the content. 
      The fees would serve to cut down on the number of people who ask for help and maybe encourage some of the people to actually pay attention to what is said rather than do their own thing. That actually turns out to be 90% of the issues. I spent 6 hours helping one individual last week I must have asked him 20 times did you do exactly like I said in the video even pointed directly to the section. When he finally sent me a copy of the what he entered I knew then and there he had not. I circled it and I pointed out that wasn't what I said to do in the video. I didn't tell him what was wrong and how I knew that way he would go back and actually follow what it said to do. He then reported it worked. Yea, no kidding following directions works. But hey isn't alone and well its part of the learning process.

      So the point of this isn't to be a gripe session. I'm just looking for a bit of feed back. Do you think the fees are unreasonable?
      Should I keep the youtube channel and do just the fees with patreon or do you think locking the content to my site and require a subscription is an idea.

      I'm just looking at the fact it is unrealistic to think youtube/google will actually get stuff right or that youtube viewers will actually bother to start looking for more accurate videos. 
    • By Balma Alparisi
      i got error 1282 in my code.
      sf::ContextSettings settings; settings.majorVersion = 4; settings.minorVersion = 5; settings.attributeFlags = settings.Core; sf::Window window; window.create(sf::VideoMode(1600, 900), "Texture Unit Rectangle", sf::Style::Close, settings); window.setActive(true); window.setVerticalSyncEnabled(true); glewInit(); GLuint shaderProgram = createShaderProgram("FX/Rectangle.vss", "FX/Rectangle.fss"); float vertex[] = { -0.5f,0.5f,0.0f, 0.0f,0.0f, -0.5f,-0.5f,0.0f, 0.0f,1.0f, 0.5f,0.5f,0.0f, 1.0f,0.0f, 0.5,-0.5f,0.0f, 1.0f,1.0f, }; GLuint indices[] = { 0,1,2, 1,2,3, }; GLuint vao; glGenVertexArrays(1, &vao); glBindVertexArray(vao); GLuint vbo; glGenBuffers(1, &vbo); glBindBuffer(GL_ARRAY_BUFFER, vbo); glBufferData(GL_ARRAY_BUFFER, sizeof(vertex), vertex, GL_STATIC_DRAW); GLuint ebo; glGenBuffers(1, &ebo); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo); glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices,GL_STATIC_DRAW); glVertexAttribPointer(0, 3, GL_FLOAT, false, sizeof(float) * 5, (void*)0); glEnableVertexAttribArray(0); glVertexAttribPointer(1, 2, GL_FLOAT, false, sizeof(float) * 5, (void*)(sizeof(float) * 3)); glEnableVertexAttribArray(1); GLuint texture[2]; glGenTextures(2, texture); glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, texture[0]); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); sf::Image* imageOne = new sf::Image; bool isImageOneLoaded = imageOne->loadFromFile("Texture/container.jpg"); if (isImageOneLoaded) { glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, imageOne->getSize().x, imageOne->getSize().y, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageOne->getPixelsPtr()); glGenerateMipmap(GL_TEXTURE_2D); } delete imageOne; glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, texture[1]); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); sf::Image* imageTwo = new sf::Image; bool isImageTwoLoaded = imageTwo->loadFromFile("Texture/awesomeface.png"); if (isImageTwoLoaded) { glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, imageTwo->getSize().x, imageTwo->getSize().y, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageTwo->getPixelsPtr()); glGenerateMipmap(GL_TEXTURE_2D); } delete imageTwo; glUniform1i(glGetUniformLocation(shaderProgram, "inTextureOne"), 0); glUniform1i(glGetUniformLocation(shaderProgram, "inTextureTwo"), 1); GLenum error = glGetError(); std::cout << error << std::endl; sf::Event event; bool isRunning = true; while (isRunning) { while (window.pollEvent(event)) { if (event.type == event.Closed) { isRunning = false; } } glClear(GL_COLOR_BUFFER_BIT); if (isImageOneLoaded && isImageTwoLoaded) { glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, texture[0]); glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, texture[1]); glUseProgram(shaderProgram); } glBindVertexArray(vao); glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, nullptr); glBindVertexArray(0); window.display(); } glDeleteVertexArrays(1, &vao); glDeleteBuffers(1, &vbo); glDeleteBuffers(1, &ebo); glDeleteProgram(shaderProgram); glDeleteTextures(2,texture); return 0; } and this is the vertex shader
      #version 450 core layout(location=0) in vec3 inPos; layout(location=1) in vec2 inTexCoord; out vec2 TexCoord; void main() { gl_Position=vec4(inPos,1.0); TexCoord=inTexCoord; } and the fragment shader
      #version 450 core in vec2 TexCoord; uniform sampler2D inTextureOne; uniform sampler2D inTextureTwo; out vec4 FragmentColor; void main() { FragmentColor=mix(texture(inTextureOne,TexCoord),texture(inTextureTwo,TexCoord),0.2); } I was expecting awesomeface.png on top of container.jpg

    • By khawk
      We've just released all of the source code for the NeHe OpenGL lessons on our Github page at https://github.com/gamedev-net/nehe-opengl. code - 43 total platforms, configurations, and languages are included.
      Now operated by GameDev.net, NeHe is located at http://nehe.gamedev.net where it has been a valuable resource for developers wanting to learn OpenGL and graphics programming.

      View full story
    • By TheChubu
      The Khronos™ Group, an open consortium of leading hardware and software companies, announces from the SIGGRAPH 2017 Conference the immediate public availability of the OpenGL® 4.6 specification. OpenGL 4.6 integrates the functionality of numerous ARB and EXT extensions created by Khronos members AMD, Intel, and NVIDIA into core, including the capability to ingest SPIR-V™ shaders.
      SPIR-V is a Khronos-defined standard intermediate language for parallel compute and graphics, which enables content creators to simplify their shader authoring and management pipelines while providing significant source shading language flexibility. OpenGL 4.6 adds support for ingesting SPIR-V shaders to the core specification, guaranteeing that SPIR-V shaders will be widely supported by OpenGL implementations.
      OpenGL 4.6 adds the functionality of these ARB extensions to OpenGL’s core specification:
      GL_ARB_gl_spirv and GL_ARB_spirv_extensions to standardize SPIR-V support for OpenGL GL_ARB_indirect_parameters and GL_ARB_shader_draw_parameters for reducing the CPU overhead associated with rendering batches of geometry GL_ARB_pipeline_statistics_query and GL_ARB_transform_feedback_overflow_querystandardize OpenGL support for features available in Direct3D GL_ARB_texture_filter_anisotropic (based on GL_EXT_texture_filter_anisotropic) brings previously IP encumbered functionality into OpenGL to improve the visual quality of textured scenes GL_ARB_polygon_offset_clamp (based on GL_EXT_polygon_offset_clamp) suppresses a common visual artifact known as a “light leak” associated with rendering shadows GL_ARB_shader_atomic_counter_ops and GL_ARB_shader_group_vote add shader intrinsics supported by all desktop vendors to improve functionality and performance GL_KHR_no_error reduces driver overhead by allowing the application to indicate that it expects error-free operation so errors need not be generated In addition to the above features being added to OpenGL 4.6, the following are being released as extensions:
      GL_KHR_parallel_shader_compile allows applications to launch multiple shader compile threads to improve shader compile throughput WGL_ARB_create_context_no_error and GXL_ARB_create_context_no_error allow no error contexts to be created with WGL or GLX that support the GL_KHR_no_error extension “I’m proud to announce OpenGL 4.6 as the most feature-rich version of OpenGL yet. We've brought together the most popular, widely-supported extensions into a new core specification to give OpenGL developers and end users an improved baseline feature set. This includes resolving previous intellectual property roadblocks to bringing anisotropic texture filtering and polygon offset clamping into the core specification to enable widespread implementation and usage,” said Piers Daniell, chair of the OpenGL Working Group at Khronos. “The OpenGL working group will continue to respond to market needs and work with GPU vendors to ensure OpenGL remains a viable and evolving graphics API for all its customers and users across many vital industries.“
      The OpenGL 4.6 specification can be found at https://khronos.org/registry/OpenGL/index_gl.php. The GLSL to SPIR-V compiler glslang has been updated with GLSL 4.60 support, and can be found at https://github.com/KhronosGroup/glslang.
      Sophisticated graphics applications will also benefit from a set of newly released extensions for both OpenGL and OpenGL ES to enable interoperability with Vulkan and Direct3D. These extensions are named:
      GL_EXT_memory_object GL_EXT_memory_object_fd GL_EXT_memory_object_win32 GL_EXT_semaphore GL_EXT_semaphore_fd GL_EXT_semaphore_win32 GL_EXT_win32_keyed_mutex They can be found at: https://khronos.org/registry/OpenGL/index_gl.php
      Industry Support for OpenGL 4.6
      “With OpenGL 4.6 our customers have an improved set of core features available on our full range of OpenGL 4.x capable GPUs. These features provide improved rendering quality, performance and functionality. As the graphics industry’s most popular API, we fully support OpenGL and will continue to work closely with the Khronos Group on the development of new OpenGL specifications and extensions for our customers. NVIDIA has released beta OpenGL 4.6 drivers today at https://developer.nvidia.com/opengl-driver so developers can use these new features right away,” said Bob Pette, vice president, Professional Graphics at NVIDIA.
      "OpenGL 4.6 will be the first OpenGL release where conformant open source implementations based on the Mesa project will be deliverable in a reasonable timeframe after release. The open sourcing of the OpenGL conformance test suite and ongoing work between Khronos and X.org will also allow for non-vendor led open source implementations to achieve conformance in the near future," said David Airlie, senior principal engineer at Red Hat, and developer on Mesa/X.org projects.

      View full story
    • By _OskaR
      Hi,
      I have an OpenGL application but without possibility to wite own shaders.
      I need to perform small VS modification - is possible to do it in an alternative way? Do we have apps or driver modifictions which will catch the shader sent to GPU and override it?
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