OpenGL ortho projection issue with rendering shadows - c++

Question

I've been trying to implement shadow mapping into my OpenGL engine in SFML 2.2, and they don't seem to be rendering right. I believe I narrowed down the issue to the ortho projection used to calculate the shadows.
/* before the main loop, creating the depth buffer for shadow mapping */
glm::vec3 lightPos(glm::vec3(-45.f, 45.f, -40.f));
const GLuint SHADOW_WIDTH = 1024, SHADOW_HEIGHT = 1024;
GLuint depthMapFBO;
glGenFramebuffers(1, &depthMapFBO);
GLuint depthMap;
glGenTextures(1, &depthMap);
glBindTexture(GL_TEXTURE_2D, depthMap);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, SHADOW_WIDTH, SHADOW_HEIGHT, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL);
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_TO_BORDER);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
GLfloat borderColor[] = { 1.0, 1.0, 1.0, 1.0 };
glTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_BORDER_COLOR, borderColor);
glBindFramebuffer(GL_FRAMEBUFFER, depthMapFBO);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, depthMap, 0);
glDrawBuffer(GL_NONE);
glReadBuffer(GL_NONE);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
/* in the main loop, sending information to the appropiate shaders and setting viewports */
glm::mat4 lightProjection, lightView;
glm::mat4 lightSpaceMatrix;
GLfloat near_plane = 1.f, far_plane = 300.f;
lightProjection = glm::ortho(-10.f, 10.f, -10.f, 10.f, near_plane, far_plane);
lightView = glm::lookAt(lightPos, glm::vec3(0.0f), glm::vec3(0.0, 1.0, 0.0));
lightSpaceMatrix = lightProjection * lightView;
glUseProgram(simpleDepthShader);
glUniformMatrix4fv(glGetUniformLocation(simpleDepthShader, "lightSpaceMat"), 1, GL_FALSE, glm::value_ptr(lightSpaceMatrix));
glViewport(0, 0, SHADOW_WIDTH, SHADOW_HEIGHT);
glBindFramebuffer(GL_FRAMEBUFFER, depthMapFBO);
glClear(GL_DEPTH_BUFFER_BIT);
RenderScene();
glBindFramebuffer(GL_FRAMEBUFFER, 0);
// reset viewport, and display the scene as normal
glViewport(0, 0, window.getSize().x, window.getSize().y);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glUniform3fv(glGetUniformLocation(lightingShader, "lightPos_shade"), 1, &lightPos[0]);
glUniform3fv(glGetUniformLocation(lightingShader, "viewPos"), 1, &getPos()[0]);
glUniformMatrix4fv(glGetUniformLocation(lightingShader, "lightSpaceMat"), 1, GL_FALSE, glm::value_ptr(lightSpaceMatrix));
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, depthMap);
RenderScene();
I've applied the view and projection matrix to the camera to see what the light sees, and this was the result (along with the view from the depth buffer).
Here's what the scene looks like with the shadows (which the shadow for the stall doesn't even cast onto itself for some reason).

Answer 1

It seems that your shader doesn't fetch your shadow pixels correctly.
When you transform your vertices with your light matrix they are in the [-1, 1] range, but texture sampling is in the range [0, 1].
http://www.opengl-tutorial.org/intermediate-tutorials/tutorial-16-shadow-mapping/