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ScherzkeCks

Member Since 15 Aug 2013
Offline Last Active Sep 30 2013 03:06 PM
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Topics I've Started

[Solved]Can't render Text

19 September 2013 - 10:38 AM

Hi everybody,

 

I have been staring at this code for 3 days now and rewritten it 2 times with no effect. I know, that the texture and the shaders get loaded just fine (confirmed that using OpenGL Profiler on Mac). The shaders work as tested with my normal draws. But the function posted below doesn't put out anything. All the values in the vectors supplied to OpenGL are fine as well. I also tried using simple arrays instead of vectors(which shouldn't make a difference) to no avail. Can somebody tell me what it is?

bool Text::drawText(int x, int y, std::string text) {
	if (programID == 0)
	{
		return false;
	}
	if (textureID == 0)
	{
		return false;
	}

	int xOffset = 0;
    std::vector<glm::vec2> vertices;
    std::vector<glm::vec2> uvCoordinats;
	for (int i = 0; i < text.size(); ++i)
	{
		int id = text[i];
		for (int j = 0; j < glyphCount; ++j)
		{
			if (glyphs[j].id == id)
			{
				/**
				 * calculate vertices and stuff
				 * Layout is as follows:
				 *     v1    v2
				 *     ------
				 *     |  / |
				 *     | /  |
				 *     ------
				 *     v3    4
				 */
                
                
                glm::vec2 v1 = glm::vec2(x + xOffset + glyphs[j].xoffset, y + glyphs[j].yoffset);
                glm::vec2 v2 = glm::vec2(x + xOffset + glyphs[j].xoffset + glyphs[j].width, y + glyphs[j].yoffset);
                glm::vec2 v3 = glm::vec2(x + xOffset + glyphs[j].xoffset,y + glyphs[j].yoffset + glyphs[j].height);
                glm::vec2 v4 = glm::vec2(x + xOffset + glyphs[j].xoffset + glyphs[j].width, y + glyphs[j].yoffset + glyphs[j].height);
                
                vertices.push_back(v1);
                vertices.push_back(v2);
                vertices.push_back(v3);
                
                vertices.push_back(v3);
                vertices.push_back(v2);
                vertices.push_back(v4);
                
                glm::vec2 uv1 = glm::vec2((GLfloat)(glyphs[j].x)/ textureWidth, (GLfloat)(glyphs[j].y) / textureHeight);
                glm::vec2 uv2 = glm::vec2((GLfloat)(glyphs[j].x + glyphs[j].width) / textureWidth,(GLfloat)(glyphs[j].y) / textureHeight);
                glm::vec2 uv3 = glm::vec2((GLfloat)(glyphs[j].x) /textureWidth,(GLfloat)(glyphs[j].y + glyphs[j].height) /textureHeight);
                glm::vec2 uv4 = glm::vec2((GLfloat)(glyphs[j].x + glyphs[j].width) / textureWidth,(GLfloat)(glyphs[j].y + glyphs[j].height) /textureHeight);
                
                
                uvCoordinats.push_back(uv1);
                uvCoordinats.push_back(uv2);
                uvCoordinats.push_back(uv3);
                
                uvCoordinats.push_back(uv3);
                uvCoordinats.push_back(uv2);
                uvCoordinats.push_back(uv4);

                xOffset += glyphs[j].advance;
				break;
			}
		}
	}
    
    //time to draw
    glUseProgram(programID);
    
    glBindVertexArray(0);
    
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, textureID);
    GLuint textureSampler = glGetUniformLocation(programID,"myTextureSampler");
    glUniform1i(textureSampler,0);
    
    
    GLuint buffers[2];
    glGenBuffers(2,buffers);
    
    glEnableVertexAttribArray(RENDER_POSITION_LOCATION);
    glBindBuffer(GL_ARRAY_BUFFER,buffers[0]);
    glBufferData(GL_ARRAY_BUFFER,vertices.size() * sizeof(glm::vec2),&vertices[0],GL_STATIC_DRAW);
    glVertexAttribPointer(RENDER_POSITION_LOCATION,2,GL_FLOAT,GL_FALSE,0,0);
    
    glEnableVertexAttribArray(RENDER_UV_LOCATION);
    glBindBuffer(GL_ARRAY_BUFFER,buffers[1]);
    glBufferData(GL_ARRAY_BUFFER,uvCoordinats.size() * sizeof(glm::vec2),&uvCoordinats[0],GL_STATIC_DRAW);
    glVertexAttribPointer(RENDER_UV_LOCATION,2,GL_FLOAT,GL_FALSE,0,0);
    
    
    glDrawArrays(GL_TRIANGLES, 0, (GLint)vertices.size());
    
    glDeleteBuffers(2,buffers);
    glBindTexture(GL_TEXTURE_2D,0);

	return true;
}

And the Shaders for the sake of it:

Vertex:

#version 150
in vec2 in_Position;
in vec2 in_UV;

out vec2 ex_UV;

void main(void)
{
    //Position is in a Range of [0,500]*[0,500] and has to be mapped to [-1,1]*[-1,1]
    vec2 out_Position = in_Position - vec2(250,250);
    out_Position = out_Position / vec2(250,250);
	gl_Position = vec4(out_Position,0,1);
	ex_UV = in_UV;
}

Fragment:

#version 150
in vec2 ex_UV;

out vec4 out_Color;

uniform sampler2D myTextureSampler;

void main(void)
{
	out_Color = texture(myTextureSampler, ex_UV);
}

[Solved]Different draw with every launch

15 August 2013 - 01:57 PM

Hi,

 

can somebody explain to me why the same Program just launched over and over again results in different drawing output?

The Data is static so it doesn't change. I attached two sampleImages that show a partly rendered Sphere where there should be a full sphere

 

The code show the actual Code to draw the sphere, the if(vertexArrayObjectName == 0) only get called once and the data returned in currentObject->getData() is always the same.

 

Thanks so much in advance

 

Stefan

RenderObject *currentObject = objectsToRender.at(i);
		GLuint vertexArrayObjectName = currentObject->getVertexArrayName();
		if (vertexArrayObjectName == 0)
		{
			//Create vertexarrayobject and buffers etc.
			GLfloat* vertices = NULL;
			GLfloat* normals = NULL;
			GLuint* indices = NULL;
			GLfloat* uvCoordinates = NULL;
			int verticesCount;
			int indicesCount;
			short textureWidth, textureHeight;
			char* textureData = NULL;
			try {
				currentObject->getData(&vertices, &normals, &indices, &uvCoordinates, &verticesCount, &indicesCount, &textureWidth, &textureHeight, &textureData);
			}
			catch (ExceptionFile* e) {
				printf("%s\n", e->what());
				//TODO: remove from objectHandler and further error-Handling
				continue;
			}

			//creating vertexarray
			glGenVertexArrays(1,&vertexArrayObjectName);
			glBindVertexArray(vertexArrayObjectName);

			currentObject->setVertexArrayName(vertexArrayObjectName);

			//create the buffers belonging to this vertexarray
			GLuint vboId;
			glGenBuffers(1,&vboId);
			glBindBuffer(GL_ARRAY_BUFFER,vboId);
			glBufferData(GL_ARRAY_BUFFER,verticesCount * sizeof(GLfloat) * 4,vertices, GL_STATIC_DRAW);
			glVertexAttribPointer(RENDER_POSITION_LOCATION,4,GL_FLOAT,GL_FALSE,0,0);
			glEnableVertexAttribArray(RENDER_POSITION_LOCATION);

			//normalBuffer
			GLuint normalBuffer;
			glGenBuffers(1,&normalBuffer);
			glBindBuffer(GL_ARRAY_BUFFER,normalBuffer);
			glBufferData(GL_ARRAY_BUFFER, verticesCount * 4 * sizeof(GLfloat),normals, GL_STATIC_DRAW);
			glVertexAttribPointer(RENDER_NORMALS_LOCATION,4,GL_FLOAT,GL_FALSE,0,NULL);
			glEnableVertexAttribArray(RENDER_NORMALS_LOCATION);

			//uvCoordinatesBuffer
			GLuint uvCoordinatesID;
			glGenBuffers(1,&uvCoordinatesID);
			glBindBuffer(GL_ARRAY_BUFFER,uvCoordinatesID);
			glBufferData(GL_ARRAY_BUFFER,verticesCount * sizeof(GLfloat) * 2,uvCoordinates,GL_STATIC_DRAW);
			glVertexAttribPointer(RENDER_UV_LOCATION,2,GL_FLOAT,GL_FALSE,0,0);
			glEnableVertexAttribArray(RENDER_UV_LOCATION);

			GLuint indicesID;
			glGenBuffers(1,&indicesID);
			glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,indicesID);
			glBufferData(GL_ELEMENT_ARRAY_BUFFER,indicesCount * sizeof(GLuint),indices,GL_STATIC_DRAW);

			//Texture
			GLuint textureID;
			glGenTextures(1, &textureID);
			glBindTexture(GL_TEXTURE_2D, textureID);
			glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, textureWidth, textureHeight, 0, GL_BGR, GL_UNSIGNED_BYTE, textureData);

			currentObject->setTextureID(textureID);

		}
		glActiveTexture(GL_TEXTURE0);
		glBindTexture(GL_TEXTURE_2D,currentObject->getTextureID());
		glUniform1i(textureSampler,0);

		glm::mat4  modelMatrix = currentObject->getModelMatrix();

		glUniformMatrix4fv(modelMatrixLocation,1,GL_FALSE,&modelMatrix[0][0]);

		glBindVertexArray(vertexArrayObjectName);

		glDrawElements(GL_TRIANGLES,currentObject->getIndicesCount(),GL_UNSIGNED_INT,0);

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