Added PBO, lower overall performance but no more drops near walls

1 files changed, 46 insertions, 20 deletions

diff --git a/src/main.c b/src/main.c
index 3069e66..0d08d16 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,3 +1,4 @@
+#include <GL/glew.h> // must come before glfw3
 #include <GLFW/glfw3.h>
 #include <stdio.h>
 #include <math.h>
@@ -35,7 +36,7 @@ typedef struct {
 } ColorRGB;
 
 // honest- this function can from chatgpt- cross-reference this with other raycasting guides
-void raycast(Player *player, int width, int height) {
+void raycast(Player *player, GLubyte *pixels, int width, int height) {
     	int screen_width = width;
     	int screen_height = height;
 
@@ -102,7 +103,7 @@ void raycast(Player *player, int width, int height) {
 		else           { perp_wall_dist = (map_y - player->pos_y + (1 - step_y) / 2) / ray_dir_y; }
 
 		// fog effect
-		float fog_distance = 20.0f;
+		float fog_distance = 15.0f;
 		float scale_factor = 1.0f - perp_wall_dist / fog_distance;
 		if (scale_factor < 0.0f) { scale_factor = 0.0f; }
 		
@@ -120,11 +121,6 @@ void raycast(Player *player, int width, int height) {
 
 
 		// colors :)
-
-		// TODO: currently, this effects both inside and outside faces
-		// which creates some awkward coloring issues with the outer walls.
-		// this may not be an issue in the final release, depending how walls
-		// are handled, but worth noting now.
 		ColorRGB color;
 		if (world_map[map_x][map_y] == 1)	color = (ColorRGB){.r = 255, .g = 255, .b = 255};
 		else if (world_map[map_x][map_y] == 2)	color = (ColorRGB){.r = 255, .g = 0, .b = 0};
@@ -147,15 +143,20 @@ void raycast(Player *player, int width, int height) {
 		color.g *= scale_factor;
 		color.b *= scale_factor;
 
-		// TODO: recommended to put this in its own function or something at some point,
-		// as it deals with library calls outside of this function's scope
-		
-		for (int y = start_y; y < end_y; y++) {
-			glBegin(GL_LINES);
-			glColor3ub(color.r, color.g, color.b);
-			glVertex2i(x, start_y);
-			glVertex2i(x, end_y);
-			glEnd();
+		int index;
+		for (int y = 0; y < screen_height; y++) {
+			index = y * screen_width * 3 + x * 3;
+			if (y >= start_y && y <= end_y) {
+				// draw something
+				pixels[index] = color.r;
+				pixels[index+1] = color.g;
+				pixels[index+2] = color.b;
+			} else {
+				// fill blank space
+				pixels[index] = 0;	
+				pixels[index+1] = 0;	
+				pixels[index+2] = 0;	
+			}
 		}
 
     	}
@@ -163,6 +164,7 @@ void raycast(Player *player, int width, int height) {
 
 int main(int argc, char *argv[]) {
 	GLFWwindow* window;
+
 	double mouse_x;
 	double mouse_y;
 
@@ -175,7 +177,7 @@ int main(int argc, char *argv[]) {
 	player.plane_x = 0.0f; // FOV related
 	player.plane_y = 0.66f; // FOV related
 	player.look_angle = 0.0f;
-	player.move_speed = 0.02f;
+	player.move_speed = 0.035f;
 	player.sensitivity = 0.001f;
 
 	// initiate glfw library
@@ -216,6 +218,19 @@ int main(int argc, char *argv[]) {
 	// TODO: render FPS with freetype or something as opposed to updating title
 	char title[200];
 
+	// setup pbo for optimized performance
+	if (glewInit() != GLEW_OK) { 
+		printf("Failed to initiate GLEW.\n");
+		return -1;
+	}
+	GLuint pbo = 0;
+
+	glGenBuffers(1, &pbo);
+	glBindBuffer(GL_PIXEL_UNPACK_BUFFER, pbo);
+	glBufferData(GL_PIXEL_UNPACK_BUFFER, mode->width * mode->height * 3, 0, GL_STREAM_DRAW);
+
+	int index = 0;
+	glViewport(0, 0, mode->width, mode->height);
 	while (!glfwWindowShouldClose(window)) {
 
 		// Stop loop if window isn't focused
@@ -233,22 +248,33 @@ int main(int argc, char *argv[]) {
 			last_time += 1.0;
 		}
 
+
 		// clear window
 		glClear(GL_COLOR_BUFFER_BIT);
 		glLoadIdentity();
 
-
 		// main raycast function
 		move_player(&player, window, &mouse_x, &mouse_y, mode->width, mode->height);
-		raycast(&player, mode->width, mode->height);
+		GLubyte* pixels = (GLubyte*)glMapBuffer(GL_PIXEL_UNPACK_BUFFER, GL_WRITE_ONLY);
+		raycast(&player, pixels, mode->width, mode->height);
 
+		// pbo
+		glUnmapBuffer(GL_PIXEL_UNPACK_BUFFER);
+		glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+		glPixelStorei(GL_UNPACK_ROW_LENGTH, mode->width);
+		glWindowPos2i(0, 0);
+		glDrawPixels(mode->width, mode->height, GL_RGB, GL_UNSIGNED_BYTE, 0);
+
+		
 		glfwSwapBuffers(window);
 		glfwPollEvents();
 
 	}
 
+	printf("Terminating GLFW...\n");
 	glfwTerminate();
-	printf("Terminating program...\n");
+	printf("Clearing buffer...\n");
+	glDeleteBuffers(1, &pbo);
 	return 0;
 
 }