Shadow.cpp

#include "Shadow.h"
#include "Window.h"

const unsigned int SHADOW_WIDTH = 1024, SHADOW_HEIGHT = 1024;
glm::vec3 lightPos(20.0f, 20.0f, 20.0f);

Shadow::Shadow() {
	float borderColor[] = { 1.0, 1.0, 1.0, 1.0 };
	glGenFramebuffers(1, &depthMapFBO);
	// create depth texture
	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);
	glTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_BORDER_COLOR, borderColor);
	// attach depth texture as FBO's depth buffer
	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);

}


void Shadow::first_pass(GLuint shaderProgram) {
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	// 1. render depth of scene to texture (from light's perspective)
	// --------------------------------------------------------------
	glm::mat4 lightProjection, lightView;
	float near_plane = 1.0f, far_plane = 1000.0f;
	lightProjection = glm::perspective(glm::radians(45.0f), (GLfloat)SHADOW_WIDTH / (GLfloat)SHADOW_HEIGHT, near_plane, far_plane); // note that if you use a perspective projection matrix you'll have to change the light position as the current light position isn't enough to reflect the whole scene
	//lightProjection = glm::ortho(-10.0f, 10.0f, -10.0f, 10.0f, near_plane, far_plane);
	lightView = glm::lookAt(lightPos, glm::vec3(0.0f), glm::vec3(0.0, 1.0, 0.0));
	lightSpaceMatrix = lightProjection * lightView;
	// render scene from light's point of view
	glUseProgram(shaderProgram);
	glUniformMatrix4fv(glGetUniformLocation(shaderProgram, "lightSpaceMatrix"), 1, GL_FALSE, &lightSpaceMatrix[0][0]);
	//shaderProgram.setMat4("lightSpaceMatrix", lightSpaceMatrix);

	glViewport(0, 0, SHADOW_WIDTH, SHADOW_HEIGHT);
	glBindFramebuffer(GL_FRAMEBUFFER, depthMapFBO);
	glClear(GL_DEPTH_BUFFER_BIT);
	renderScene(shaderProgram);
	glBindFramebuffer(GL_FRAMEBUFFER, 0);

	// reset viewport
	glViewport(0, 0, Window::width, Window::height);
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
}
void Shadow::second_pass(GLuint shaderProgram) {
	glViewport(0, 0, Window::width, Window::height);
	glUseProgram(shaderProgram);
	GLuint uProjection = glGetUniformLocation(shaderProgram, "projection");
	GLuint uView = glGetUniformLocation(shaderProgram, "View");
	glUniformMatrix4fv(uProjection, 1, GL_FALSE, &Window::P[0][0]);
	glUniformMatrix4fv(uView, 1, GL_FALSE, &Window::V[0][0]);
	glUniform1i(glGetUniformLocation(shaderProgram, "diffuseTexture"), 0);
	glUniform1i(glGetUniformLocation(shaderProgram, "shadowMap"), 1);
	//shader.setInt("diffuseTexture", 0);
	//shader.setInt("shadowMap", 1);
	// set light uniforms
	glUniform3f(glGetUniformLocation(shaderProgram, "lightPos"), lightPos.x, lightPos.y, lightPos.z);
	glUniform3f(glGetUniformLocation(shaderProgram, "viewPos"), Window::cam_pos.x, Window::cam_pos.y, Window::cam_pos.z);
	//shader.setVec3("viewPos", camera.Position);
	//shader.setVec3("lightPos", lightPos);
	glUniformMatrix4fv(glGetUniformLocation(shaderProgram, "lightSpaceMatrix"), 1, GL_FALSE, &lightSpaceMatrix[0][0]);
	//shader.setMat4("lightSpaceMatrix", lightSpaceMatrix);
	glActiveTexture(GL_TEXTURE1);
	glBindTexture(GL_TEXTURE_2D, depthMap);
	renderScene(shaderProgram);
}

void  Shadow::renderScene(GLuint shaderProgram)
{
	for (auto geo : Window::geos) {
		geo->drawDepth(shaderProgram);
	}
}