Why is this texture not showing up? - c++

I am following the tutorial from learnopengl.com to make a game engine.
I am using stb_image.h to load the textures, and my own header file to compile and link the shaders.
I got to the part in Getting Started/Textures where the container.jpg texture is supposed to fill up the rectangle on the window. But whenever I compile and run the code the texture does not appear anywhere in the window. This is my texture loading code:
// Load and create a texture
unsigned int texture1;
glGenTextures(1, &texture1);
glBindTexture(GL_TEXTURE_2D, texture1);
// Set the texture wrapping parameters
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
// Set texture filtering parameters
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
// Load image, create texture, and generate minmaps
int width, height, nrChannels;
unsigned char* data = stbi_load("C:\\Users\\Lucas\\OneDrive\\Desktop\\C++ Projects\\Working Game Engine\\container.jpg", &width, &height, &nrChannels, 0);
if (data) {
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
glGenerateMipmap(GL_TEXTURE_2D);
}
else {
std::cout << "Failed to load texture(s)\n";
}
These are the quad's coords:
float vertices[] = {
// Positions // Colors // Texture Coords
0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f,
0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f,
-0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f,
-0.5f, 0.5f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f
};
unsigned int indices[] = {
0, 1, 3,
1, 2, 3
};
Render code:
// Process inputs
processInput(window);
// Render
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
// Bind Texture
glBindTexture(GL_TEXTURE_2D, texture1);
// Render Container
ourShader.use();
glBindVertexArray(VAO);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
// Swap buffers and poll IO events (Key pressed/released, mouse moved etc.)
glfwSwapBuffers(window);
glfwPollEvents();
Vertex shader code:
#version 460 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aColor;
layout (location = 2) in vec2 aTexCoord;
out vec3 ourColor;
out vec2 TexCoord;
void main()
{
gl_Position = vec4(aPos, 1.0);
ourColor = aColor;
TexCoord = vec2(aTexCoord.x, aTexCoord.y);
}
Fragment shader code:
#version 460 core
out vec4 FragColor;
in vec3 ourColor;
in vec2 TexCoord;
uniform sampler2D texture1;
void main()
{
FragColor = texture(texture1, TexCoord);
}
Note that no error codes are returned from the image loader or shader compilers.
The rectangle appears like this.

You need to update the texture1 uniform like this:
glUniform1i(glGetUniformLocation(program_id, "texture1"), 0);

So it turns out I didn't glEnableVertexAttribArray(); the texture coords. Quite embarrassing.

Related

Why is my cubemap rendered to FBO only rendering one side of my cube?

I want to render my scene into a cubemap FBO but I can't seem to get it working properly. Only 1 side of my cube is showing the rendered cubemap as a test.
This is my FBO setup:
// create cubemap FBO
unsigned int cubemapFBO;
glGenFramebuffers(1, &cubemapFBO);
glBindFramebuffer(GL_FRAMEBUFFER, cubemapFBO);
// create color cubemap texture
unsigned int colorCubemap;
glGenTextures(1, &colorCubemap);
glBindTexture(GL_TEXTURE_CUBE_MAP, colorCubemap);
for (unsigned int i = 0; i < 6; ++i)
{
glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, GL_RGBA8, size, size, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
}
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
// create depth cubemap
unsigned int depthCubemap;
glGenTextures(1, &depthCubemap);
glBindTexture(GL_TEXTURE_CUBE_MAP, depthCubemap);
for (unsigned int i = 0; i < 6; ++i)
{
glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, GL_DEPTH_COMPONENT24, size, size, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL);
}
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
// attach depth texture as FBO's depth buffer
glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, colorCubemap, 0);
glFramebufferTexture(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, depthCubemap, 0);
//glDrawBuffer(GL_COLOR_ATTACHMENT0);
if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
std::cout << "ERROR on cubemapFBO: Framebuffer is not complete!" << std::endl;
glBindFramebuffer(GL_FRAMEBUFFER, 0);
// -- End cubemap FBO -- //
This is my projection and view matrices to capture 6 cubemap faces
// set up projection and view matrices for capturing 6 cubemap faces
glm::mat4 captureProjection = glm::perspective(glm::radians(90.0f), 1.0f, 0.1f, 10.0f);
glm::mat4 captureViews[] = {
captureProjection * glm::lookAt(glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3( 1.0f, 0.0f, 0.0f), glm::vec3(0.0f, -1.0f, 0.0f)),
captureProjection * glm::lookAt(glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3(-1.0f, 0.0f, 0.0f), glm::vec3(0.0f, -1.0f, 0.0f)),
captureProjection * glm::lookAt(glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3( 0.0f, -1.0f, 0.0f), glm::vec3(0.0f, 0.0f, 1.0f)),
captureProjection * glm::lookAt(glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3( 0.0f, 1.0f, 0.0f), glm::vec3(0.0f, 0.0f, -1.0f)),
captureProjection * glm::lookAt(glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3( 0.0f, 0.0f, -1.0f), glm::vec3(0.0f, -1.0f, 0.0f)),
captureProjection * glm::lookAt(glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3( 0.0f, 0.0f, 1.0f), glm::vec3(0.0f, -1.0f, 0.0f))
};
// -- End projection and view matrices setup -- //
This is my scene rendering to cubemap FBO
// render scene to cubemap FBO
glViewport(0, 0, size, size);
glBindFramebuffer(GL_FRAMEBUFFER, cubemapFBO);
glClear(GL_DEPTH_BUFFER_BIT);
simpleDepthShader.Use();
for (unsigned int i = 0; i < 6; ++i)
{
simpleDepthShader.setMat4("shadowMatrices[" + std::to_string(i) + "]", captureViews[i]);
}
// skybox test
cubemap.Use();
glm::mat4 cubemapModel = glm::translate(glm::mat4(1.0f), positions);
//glm::mat4 cubemapRotate = glm::rotate(glm::mat4(1.0f), glm::radians(-(float)glfwGetTime() * 0.2f), glm::vec3(0.0f, 1.0f, 0.0));
//glm::mat4 cubemapRotate = glm::rotate(glm::mat4(1.0f), glm::radians(-(float)glfwGetTime() * 0.2f), glm::vec3(0.0f, 1.0f, 0.0));
//cubemapModel = cubemapModel * cubemapRotate;
cubemap.setMat4("projection", projection);
cubemap.setMat4("view", skyboxView);
cubemap.setMat4("model", cubemapModel);
glDepthFunc(GL_LEQUAL);
glDepthMask(GL_TRUE);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_CUBE_MAP, secondCubemapTexture);
renderCubemap();
glDepthFunc(GL_LESS);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
// -- End render to cubemap FBO -- //
And this is my vertex + geometry + fragment shader
#shader vertex
#version 450 core
layout (location = 0) in vec3 aPos;
uniform mat4 model;
void main()
{
gl_Position = model * vec4(aPos, 1.0);
}
#shader fragment
#version 450 core
out vec4 FragColor;
in vec4 FragPos;
void main()
{
FragColor = FragPos;
}
#shader geometry
#version 450 core
layout (triangles) in;
layout (triangle_strip, max_vertices=18) out;
uniform mat4 shadowMatrices[6];
out vec4 FragPos; // FragPos from GS (output per emitvertex)
void main()
{
for(int face = 0; face < 6; ++face)
{
gl_Layer = face; // built-in variable that specifies to which face we render.
for(int i = 0; i < 3; ++i) // for each triangle's vertices
{
FragPos = gl_in[i].gl_Position;
gl_Position = shadowMatrices[face] * FragPos;
EmitVertex();
}
EndPrimitive();
}
}
And then testing out the cubemap onto a cube with the fbo cubemap texture
// test cube with FBO cubemap
cube.Use();
cube.setMat4("projection", projection);
cube.setMat4("view", view);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, silverTeapotTexture);
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_CUBE_MAP, colorCubemap); // <-- here
glm::mat4 cubeModel = glm::translate(glm::mat4(1.0f), glm::vec3(0.0f, -0.5f, 0.0f));
cube.setMat4("model", cubeModel);
renderTexturedCube();

Fragment shader ignores texture coordinates

I am learning OpenGL through the tutorials at learnopengl.com.
I've already drawn my hand-defined 3x3 texture onto a square using 2 triangles without a shader. Using shaders, however, I don't understand this weird behavior:
The fragment shader seems to ignore texture coordinates but strangely paints my two triangles with the color of the first pixel. I tried putting garbage values into the texture coordinates and it always stays the same.
unsigned char texture_buffer[9*4] = // 3x3 texture RGBA ...
{
255,40,100,255, 100,200,200,255, 150,150,200,255,
100,100,150,255, 200,200,100,255, 150,200,150,255,
150,100,100,255, 200,100,200,255, 200,150,150,255
};
float positions_texcoords[] =
{ // x y z tex coords
0.0f, 0.0f, 0.0f, 0.0f, 0.0f,
0.5f, 0.0f, 0.0f, 1.0f, 0.0f,
0.0f, 0.5f, 0.0f, 0.0f, 1.0f,
0.5f, 0.5f, 0.0f, 1.0f, 1.0f,
0.5f, 0.0f, 0.0f, 1.0f, 0.0f,
0.0f, 0.5f, 0.0f, 0.0f, 1.0f
};
one time draw call:
GLuint texture = 0;
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 3, 3, 0,
GL_RGBA, GL_UNSIGNED_BYTE, (void *)texture_buffer );
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
unsigned int VBO, VAO;
glGenVertexArrays(1, &VAO);
glGenBuffers(1, &VBO);
glBindVertexArray(VAO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(positions_texcoords),
positions_texcoords, GL_STATIC_DRAW);
// position attribute
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
// texture coord attribute
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));
glEnableVertexAttribArray(1);
glClearColor(0.3f, 0.0f, 0.1f, 0.0f);
glClear(GL_COLOR_BUFFER_BIT);
glBindTexture(GL_TEXTURE_2D, texture);
glUseProgram(shader_program_id);
glBindVertexArray(VAO);
glDrawArrays(GL_TRIANGLES, 0, 6);
SwapBuffers(window_dc);
vertex shader:
#version 330 core
layout (location = 0) in vec3 in_pos;
layout (location = 1) in vec2 in_tex_coord;
out vec2 out_tex_coord;
void main()
{
gl_Position = vec4(in_pos, 1.0);
out_tex_coord = in_tex_coord;
}
fragment shader:
#version 330 core
out vec4 FragColor;
in vec2 in_tex_coord;
uniform sampler2D in_texture;
void main()
{
FragColor = texture(in_texture, in_tex_coord);
}
I'd appreciate any suggestions about what might be going on. Thank you.
The output of a shader stage is linked to the input of the next shader stage by its name (except when you use a layout qualifier). See interface matching rules between shader stages.
The name of the fragment shader input variable has to be the same as the name of the vertex shader output variable.
Since the name of the texture coordinate output in the vertex shader is out_tex_coord
out vec2 out_tex_coord;
the name of the corresponding input in the fragment shader has to be out_tex_coord, too:
in vec2 out_tex_coord;
void main()
{
FragColor = texture(in_texture, out_tex_coord);
}

Rendering white box textures in STB/Opengl

Program compiles fine. Quads print. Trying to insert a 32 bit png, but it only prints a white box. What am I doing wrong? I've spent a few days trying to figure it out doing countless tutorials. I don't want to give up.
GLfloat cancelButtonVert[]
{
0.1367f, -0.928f, 0.0f, 0.0f, 0.0f,
0.4833f, -0.928f, 0.0f, 1.0f, 0.0f,
0.4833f, -0.744f, 0.0f, 1.0f, 1.0f,
0.1367f, -0.744f, 0.0f, 0.0f, 1.0f
};
const unsigned int buttonIndices[]
{
0, 1, 2,
2, 3, 0,
};
......
It's all set up with in classes and functions, but I will try to show the whole draw.
.....
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(m_vertices[0]) * 5, 0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(m_vertices[0]) * 5, (void*)(sizeof(m_vertices[0]) * 3));
glEnableVertexAttribArray(1);
.....
void Texture::loadTexture()
{
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
unsigned char *texData = stbi_load(m_fileLocation.c_str(), &m_width, &m_height, &m_bitDepth, 0);
if (!texData)
{
printf("Failed to find: %s\n", m_fileLocation.c_str());
return;
}
glGenTextures(1, &m_textureId);
glBindTexture(GL_TEXTURE_2D, m_textureId);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, m_width, m_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, texData);
glGenerateMipmap(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, 0);
stbi_image_free(texData);
}
void Texture::useTexture()
{
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, m_textureId);
}
shaderList[0].useShader();
uniformModel = shaderList[0].getModelLocation();
uniformTexture = shaderList[0].getUniformTexture();
//Draw Boxes
model = glm::mat4();
model = glm::translate(model, glm::vec3(0.0f, 0.0f, 0.0f));
model = glm::scale(model, glm::vec3(1.0f, 1.0f, 1.0f));
glUniformMatrix4fv(uniformModel, 3, GL_FALSE, glm::value_ptr(model));
cancelButton.useTexture();
glUniform1i(uniformTexture, 0);
meshlist[0]->renderMesh();
The fragment shader.
#version 330
in vec4 vCol;
in vec2 TexCoord;
out vec4 color;
uniform sampler2D theTexture;
void main()
{
color = texture(theTexture, TexCoord);
}
The Vertex Shader.
#version 330
layout (location = 0) in vec3 pos;
layout (location = 1) in vec2 tex;
out vec4 vCol;
out vec2 TexCoord;
uniform mat4 model;
uniform mat4 projection;
void main()
{
gl_Position = projection * model * vec4(pos, 1.0);
vCol = vec4(clamp(pos, 0.0f, 1.0f), 1.0f);
TexCoord = tex;
}
Projection was out of wack. The reason I was getting all of those 1281 and 12 82 GLerrors was the fact that I was calling the wrong vector index, so I could see a draw. I saw a draw and assumed I was heading in the right direction.
If I called what I knew was right, all the drawing happened off screen.
What I did was delete the projection matrix in my shader since all I wanted was a 2d rendering of a gui window with calculated pixel ratios in a calculated position.
I will keep model in the shader if I want to tweak things in the future.
All of your help made me a better programmer. #Rabbid76 all of your suggestions were things I needed to do. Ty all.
Corrected Shader
#version 330
layout (location = 0) in vec3 pos;
layout (location = 1) in vec2 tex;
out vec4 vCol;
out vec2 TexCoord;
uniform mat4 model;
void main()
{
gl_Position = model * vec4(pos, 1.0);
vCol = vec4(clamp(pos, 0.0f, 1.0f), 1.0f);
TexCoord = tex;
}

Switching more than one shader program (in OpenGL-ES 2.0)

I am really having nightmare to achieve what I required in OpenGles 2.0
Before posting the code reference, let me tell what I need.
I have 2D texture fragment shader. On top of the texture I want to draw red color line. I am able to draw the line but coloring to red is not working.
Shader declaration:
static const char s_v_shader[] =
"attribute vec4 vPosition; \n"
"attribute vec2 my_Texcoor; \n"
"uniform mat4 u_TransMatrix; \n"
"varying vec2 vTexcoor; \n"
"void main() \n"
"{ \n"
" vTexcoor = my_Texcoor; \n"
" gl_Position = u_TransMatrix*vPosition; \n"
"} \n";
static const char s_f_shader[] =
"precision mediump float;\n"
"uniform sampler2D my_Sampler; \n"
"varying vec2 vTexcoor; \n"
"void main() \n"
"{ \n"
" vec4 tex = texture2D(my_Sampler, vTexcoor); \n"
" gl_FragColor = tex; \n"
"} \n";
On top of texture I am rendering video frames from camera in infinite loop.
Before rendering video, I am setting up co-ordinates of 2D texture with below code.
Now I will explain my code from main function
main()
{
const GLfloat vertices[][2] = {
{ -1.0f, -1.0f},
{ 1.0f, -1.0f},
{ -1.0f, 1.0f},
{ 1.0f, 1.0f}
};
const GLfloat texcoords[][2] = {
{ 0.0f, 1.0f},
{ 1.0f, 1.0f},
{ 0.0f, 0.0f},
{ 1.0f, 0.0f}
};
GLfloat transformMatrix[16] =
{
1.0f, 0.0f, 0.0f, 0.0f,
0.0f, 1.0f, 0.0f, 0.0f,
0.0f, 0.0f, 1.0f, 0.0f,
0.0f, 0.0f, 0.0f, 1.0f
};
// setup OpenGl environment......
Setup_coordinates()
}
Setup_coordinates()
{
LoadShaders(s_v_shader, s_f_shader);
-- Complete function defined below
// By now I should be using shader program.
// Grab location of shader attributes.
GLint locVertices = glGetAttribLocation(programHandle, "vPosition");
GLint locTexcoord = glGetAttribLocation(programHandle, "my_Texcoor");
// Transform Matrix is uniform for all vertices here.
GLint locTransformMat = glGetUniformLocation(programHandle, "u_TransMatrix");
GLint locSampler = glGetUniformLocation(programHandle, "my_Sampler");
/* Create the texture. */
glGenTextures(1, &gTexObj);
glBindTexture(GL_TEXTURE_2D, gTexObj);
if (gTexObj == 0)
{
printf("Could not load the texture \n");
return -1;
}
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glUniformMatrix4fv(locTransformMat, 1, GL_FALSE, transformMatrix);
glUniform1i(locSampler, 0);
glClearColor(0.0f, 0.5f, 0.0f, 0.0f);
glClear(GL_COLOR_BUFFER_BIT);
while(1) -- Infinite loop to render video frames on 2D texture and draw red color line.
{
// enable vertex arrays to push the data.
glEnableVertexAttribArray(locVertices);
glEnableVertexAttribArray(locTexcoord);
// set data in the arrays.
glVertexAttribPointer(locVertices, 2, GL_FLOAT, GL_FALSE, 0, &vertices[0][0]);
glVertexAttribPointer(locTexcoord, 2, GL_FLOAT, GL_FALSE, 0, &texcoords[0][0]);
Render video frames logic goes here...................................
Each frame of video is abosultely rendering fine.
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
Now comes the tricky part to draw the line and color it with red.
float red_left_1[] =
{
-0.85f, -0.9f, -0.6f, -0.5f,
};
glVertexAttribPointer ( 1, 2, GL_FLOAT, GL_FALSE, 0, red_left_1 );
glEnableVertexAttribArray (1 );
glDrawArrays ( GL_LINES , 0, 2 );
glLineWidth( width_test );
}
}
void LoadShaders(const char * vShader, const char * pShader)
{
vertShaderNum = glCreateShader(GL_VERTEX_SHADER);
pixelShaderNum = glCreateShader(GL_FRAGMENT_SHADER);
if (CompileShader(vShader, vertShaderNum) == 0)
{
printf("%d: PS compile failed.\n", __LINE__);
return;
}
if (CompileShader(pShader, pixelShaderNum) == 0)
{
printf("%d: VS compile failed.\n", __LINE__);
return;
}
programHandle = glCreateProgram();
glAttachShader(programHandle, vertShaderNum);
glAttachShader(programHandle, pixelShaderNum);
// Bind vPosition to attribute 0
glBindAttribLocation ( programHandle, 0, "vPosition" );
glLinkProgram(programHandle);
// Check if linking succeeded.
GLint linked = 0;
glGetProgramiv(programHandle, GL_LINK_STATUS, &linked);
if (!linked)
{
printf("%d: Link failed.\n", __LINE__);
// Retrieve error buffer size.
GLint errorBufSize, errorLength;
glGetShaderiv(programHandle, GL_INFO_LOG_LENGTH, &errorBufSize);
char * infoLog = (char*)malloc(errorBufSize * sizeof (char) + 1);
if (infoLog)
{
// Retrieve error.
glGetProgramInfoLog(programHandle, errorBufSize, &errorLength, infoLog);
infoLog[errorBufSize + 1] = '\0';
fprintf(stderr, "%s", infoLog);
free(infoLog);
}
return;
}
glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glUseProgram(programHandle);
}
Most of the genius peoples suggested to declare one more shader as above but replace uniform sampler2D my_Sampler with uniform vec4 color.
void main()
{
gl_FragColor = color
}
Then switch between these shader programs while showing texture and drawing color lines using glUseProgram.
I tried and absolutely given up as switching to shader program for drawing lines is not working.
Here is code for generating a colored 1x1 texture that you can use for your line (goes in your main or Setup_coordinates). With this solution you won't need another shader.
GLuint lineTexture;
glGenTextures(1, &lineTexture);
unsigned char red[4] = { 255, 0, 0, 255};
glBindTexture(GL_TEXTURE_2D, lineTexture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE, red);
glBindTexture(GL_TEXTURE_2D, 0);
Before calling glDrawArrays, use this to switch to the correct texture.
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, <lineTexture or gTexObj>);
glUniform1i(locSampler, 0);
A more general solution (that I personally implement in my OpenGL projects) is to create a white texture, add a color uniform to your shader and multiply the uniform with the texture2D return value. With this method you can create different colored lines and graphics from the same white texture, only changing the color uniform. For the video frames, you would send in a white color and the pixels will remain unchanged. This will require very few changes to your code, I'm sure you can figure it out if you think it sounds better. :)

OpenGL Shadow Map

I am trying to do a basic shadow map but for some reason, It doesn't render properly.
Video of the Problem
I render the house using a flat shader:
int shadowMapWidth = WINDOW_SIZE_X * (int)SHADOW_MAP_RATIO;
int shadowMapHeight = WINDOW_SIZE_Y * (int)SHADOW_MAP_RATIO;
// Rendering into the shadow texture.
glActiveTexture(GL_TEXTURE0);
CALL_GL(glBindTexture(GL_TEXTURE_2D, shadowTexture));
// Bind the framebuffer.
CALL_GL(glBindFramebuffer(GL_FRAMEBUFFER, shadowFBO));
//Clear it
CALL_GL(glClear(GL_DEPTH_BUFFER_BIT));
CALL_GL(glViewport(0, 0, shadowMapWidth, shadowMapHeight));
CALL_GL(glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE));
//Render stuff
flatShader.use();
flatShader["baseColor"] = glm::vec4(1.0f,1.0f,1.0f,1.0f);
flatShader["pvm"] = projectionMatrix*pointLight.viewMatrix*cursor.modelMatrix;
cursor.draw(); //binds the vao and draws
// Revert for the scene.
CALL_GL(glBindFramebuffer(GL_FRAMEBUFFER, 0));
CALL_GL(glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE));
CALL_GL(glViewport(0, 0, WINDOW_SIZE_X, WINDOW_SIZE_Y));
Notice that I only render the house. I don't render the floor in the depth-buffer pass.
Following this I render the quad that represents the floor using the following shader pair:
/* [VERT] */
#version 330
in vec3 in_Position;
in vec2 in_TexCoord;
uniform mat4 shadowMatrix;
uniform mat4 mvp;
out vec2 UV;
out vec4 shadowProj;
void main()
{
gl_Position = mvp*vec4(in_Position,1.0);
shadowProj = shadowMatrix*vec4(in_Position,1.0);
UV = in_TexCoord;
}
And the Fragment Shader:
/* [FRAG] */
#version 330
in vec2 UV;
in vec4 shadowProj;
out vec4 fragColor;
uniform sampler2D texturex;
uniform sampler2DShadow shadowMap;
void main()
{
fragColor = vec4(texture(texturex, UV).rgb,1);
float shadow = 1.0;
shadow = textureProj(shadowMap,shadowProj);
fragColor *= shadow;
}
I then draw the house again in color and ... the floor:
textureShader.use();
glUniform1i(baseImageLoc, 0); //Texture unit 0 is for base images.
glUniform1i(shadowMapLoc, 1); //Texture unit 1 is for shadow maps.
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, floorTexture);
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, shadowTexture);
textureShader["shadowMatrix"] = projectionMatrix*pointLight.viewMatrix*floorMatrix;
textureShader["mvp"] = projectionMatrix*viewMatrix*floorMatrix;
CALL_GL(glBindVertexArray(floorVAO));
CALL_GL(glDrawArrays(GL_TRIANGLES,0,18));
glfwSwapBuffers();
Has anybody seen this behavior before? Any idea what could be wrong? By the way, the light's coordinates place it directly on top of the house so the shadow should be directly below the house on the floor (but it ends up sideways).
For reference here is how I generate the shadow FBO:
int shadowMapWidth = WINDOW_SIZE_X * (int)SHADOW_MAP_RATIO;
int shadowMapHeight = WINDOW_SIZE_Y * (int)SHADOW_MAP_RATIO;
glGenTextures(1, &shadowTexture);
glBindTexture(GL_TEXTURE_2D, shadowTexture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, shadowMapWidth, shadowMapHeight, 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_BYTE, 0);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_REF_TO_TEXTURE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC, GL_LESS);
glTexImage2D(GL_TEXTURE_2D,0,GL_DEPTH_COMPONENT,shadowMapWidth,shadowMapHeight,0,GL_DEPTH_COMPONENT,GL_FLOAT,NULL);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_COMPARE_MODE,GL_COMPARE_R_TO_TEXTURE);
glBindTexture(GL_TEXTURE_2D, 0); //unbind the texture
glGenFramebuffers(1, &shadowFBO);
glBindFramebuffer(GL_FRAMEBUFFER, shadowFBO);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, shadowTexture, 0);
glDrawBuffer(GL_NONE);
glReadBuffer(GL_NONE);
if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
{ printf("GL_FRAMEBUFFER_COMPLETE error 0x%x", glCheckFramebufferStatus(GL_FRAMEBUFFER)); }
glClearDepth(1.0f); glEnable(GL_DEPTH_TEST);
// Needed when rendering the shadow map. This will avoid artifacts.
glPolygonOffset(1.0f, 0.0f); glBindFramebuffer(GL_FRAMEBUFFER, 0);
//to convert the texture coordinates to -1 ~ 1
GLfloat biasMatrixf[] = {
0.5f, 0.0f, 0.0f, 0.0f,
0.0f, 0.5f, 0.0f, 0.0f,
0.0f, 0.0f, 0.5f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f };
biasMatrix = glm::make_mat4(biasMatrixf);
It looks like you forgot to multiply your shadow matrix by the bias matrix.