chip8

commit 6a959e258e9d4fb132c9c8384e7b3dc57abf86ab
parent fbca12ac2550a029e1119dde5d0a45fea9d1027b
Author: Léo Villeveygoux <l@vgx.fr>
Date:   Wed, 15 Apr 2020 19:56:55 +0200

Add glfw/OpenGL ES 2.0 based media handling

Compile with `make MEDIA=glfw`

Diffstat:
M
Makefile
 | 
7
++++++-
A
media-glfw.c
 | 
239
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

2 files changed, 245 insertions(+), 1 deletion(-)
diff --git a/Makefile b/Makefile
@@ -1,6 +1,11 @@
 MEDIA=sdl
 
-LDLIBS=-l${MEDIA:sdl=SDL2}
+LIBS_sdl=-lSDL2
+LIBS_raylib=-lraylib
+LIBS_glfw=-lglfw -lGLESv2
+
+
+LDLIBS=${LIBS_${MEDIA}}
 
 chip8: media-${MEDIA}.o
 
diff --git a/media-glfw.c b/media-glfw.c
@@ -0,0 +1,239 @@
+#include <assert.h>
+#include <stdio.h>
+#include <string.h>
+
+#define GLFW_INCLUDE_ES2
+#include <GLFW/glfw3.h>
+
+#include "media.h"
+
+#define PIXEL_RADIUS 16
+
+#define SCREEN_WIDTH (64*PIXEL_RADIUS)
+#define SCREEN_HEIGHT (32*PIXEL_RADIUS)
+
+#define WINDOW_NAME "CHIP-8 emulator"
+
+#define NUM_PIXELS (32*64)
+
+#define SOUND_DEV_FREQ 48000
+#define SOUND_SAMPLES 1024
+#define BUZZER_FREQ 440
+#define BUZZER_VOL .05
+
+unsigned char pixels[NUM_PIXELS];
+
+GLFWwindow *window;
+
+const float vertices[] = {
+	-1.0f, -1.0f,
+	-1.0f, +1.0f,
+	+1.0f, -1.0f,
+	+1.0f, +1.0f,
+};
+
+const char *v_shader_src =
+"#version 100\n"
+"in vec2 coords;\n"
+"varying vec2 tex_coords;\n"
+"void main(){\n"
+"	gl_Position = vec4(coords.x, coords.y, 0.0, 1.0);\n"
+"	tex_coords.x = (1.0 + coords.x)/2.0;\n"
+"	tex_coords.y = (1.0 - coords.y)/2.0;\n"
+"}";
+
+const char *f_shader_src =
+"#version 100\n"
+"in lowp vec2 tex_coords;\n"
+"uniform sampler2D tex;\n"
+"void main(){\n"
+"	gl_FragColor = vec4(vec3(texture2D(tex, tex_coords).a), 1.0);\n"
+"}";
+
+
+unsigned short input;
+
+
+/* sound state*/
+int buzzer_state = 0;
+
+/*
+┌───┬───┬───┬───┐
+│ 1 │ 2 │ 3 │ C │
+├───┼───┼───┼───┤
+│ 4 │ 5 │ 6 │ D │
+├───┼───┼───┼───┤
+│ 7 │ 8 │ 9 │ E │
+├───┼───┼───┼───┤
+│ A │ 0 │ B │ F │
+└───┴───┴───┴───┘
+*/
+
+int keys[16] = {
+	GLFW_KEY_V,
+	GLFW_KEY_3, GLFW_KEY_4, GLFW_KEY_5,
+	GLFW_KEY_E, GLFW_KEY_R, GLFW_KEY_T,
+	GLFW_KEY_D, GLFW_KEY_F, GLFW_KEY_G,
+	GLFW_KEY_C, GLFW_KEY_B,
+	GLFW_KEY_6, GLFW_KEY_Y, GLFW_KEY_H, GLFW_KEY_N
+};
+
+static void buzzer_callback(void *userdata, unsigned char *stream, int len){
+	static long sample_num = 0;
+	(void) userdata;
+	for(int i=0 ; i<len ; i++){
+		if(buzzer_state == 0)
+			stream[i] = 0;
+		else /* saw waves at the moment */
+			stream[i] =
+				((sample_num++*256*BUZZER_FREQ/SOUND_DEV_FREQ)
+				 %256)*BUZZER_VOL;
+	}
+}
+
+static void key_callback(GLFWwindow* window, int key, int s, int action, int m){
+	(void) s, (void)m, (void) window;
+	for (int i=0 ; i<16 ; i++) {
+		if (key == keys[i]){
+			if (action == GLFW_PRESS)
+				input |= 1<<i;
+			else if (action == GLFW_RELEASE)
+				input ^= 1<<i;
+		}
+	}
+}
+
+void framebuffer_size_callback(GLFWwindow* window, int width, int height){
+	(void) window;
+	glViewport(0, 0, width, height);
+}
+
+static void check_shader_log(unsigned shader){
+	int success;
+	glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
+	if (!success){
+		char log[512];
+		glGetShaderInfoLog(shader, 512, NULL, log);
+		puts("Shader compile log:");
+		puts(log);
+	}
+}
+
+static void setup_shaders(void){
+	/* Create vertex shader */
+	unsigned v_shader = glCreateShader(GL_VERTEX_SHADER);
+	glShaderSource(v_shader, 1, &v_shader_src, NULL);
+	glCompileShader(v_shader);
+	check_shader_log(v_shader);
+
+	/* Create fragment shader */
+	unsigned f_shader = glCreateShader(GL_FRAGMENT_SHADER);
+	glShaderSource(f_shader, 1, &f_shader_src, NULL);
+	glCompileShader(f_shader);
+	check_shader_log(f_shader);
+
+	/* Create shader program */
+	unsigned program = glCreateProgram();
+	glAttachShader(program, v_shader);
+	glAttachShader(program, f_shader);
+	glLinkProgram(program);
+	glUseProgram(program);
+
+	/* Remove shaders */
+	glDeleteShader(v_shader);
+	glDeleteShader(f_shader);
+
+	/* Create vertex buffer */
+	unsigned VBO;
+	glGenBuffers(1, &VBO);
+	glBindBuffer(GL_ARRAY_BUFFER, VBO);
+	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+
+	/* Setup vertex input array */
+	glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, 0);
+	glEnableVertexAttribArray(0);
+}
+
+static void setup_texture(void){
+	unsigned texture;
+	glGenTextures(1, &texture);
+	glBindTexture(GL_TEXTURE_2D, texture);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, 64, 32, 0, GL_ALPHA, GL_UNSIGNED_BYTE, pixels);
+}
+
+int m_init(int argc, char **argv){
+	(void)argc, (void)argv;
+	/*TODO: check every init */
+
+	glfwInit();
+	glfwWindowHint(GLFW_CLIENT_API, GLFW_OPENGL_ES_API);
+	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
+	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
+
+	window = glfwCreateWindow(SCREEN_WIDTH, SCREEN_HEIGHT, WINDOW_NAME, NULL, NULL);
+	glfwMakeContextCurrent(window);
+
+	glViewport(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);
+	glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
+
+	glfwSwapInterval(1);
+	
+	glfwSetKeyCallback(window, key_callback);
+
+	setup_shaders();
+	setup_texture();
+	
+	glClear(GL_COLOR_BUFFER_BIT);
+
+	return 0;
+}
+
+void m_quit(void){
+	glfwDestroyWindow(window);
+
+	glfwTerminate();
+}
+
+unsigned short get_input(unsigned short old_input){
+	(void) old_input;
+	if (glfwWindowShouldClose(window))
+		return -1;
+
+	return input;
+}
+unsigned short wait_input(unsigned short input){
+	int new_input;
+	
+	while((new_input = get_input(input)) == input)
+		frame();
+
+	return new_input;
+}
+
+void clear_screen(void){
+	memset(pixels,0,NUM_PIXELS);
+	glClear(GL_COLOR_BUFFER_BIT);
+}
+
+void draw(int x, int y, int value){
+	assert(0<=x && x<64);
+	assert(0<=y && y<32);
+
+	pixels[y*64+x] = value ? 255 : 0;
+}
+
+void frame(void){
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, 64, 32, 0, GL_ALPHA, GL_UNSIGNED_BYTE, pixels);
+	glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+
+	glfwSwapBuffers(window);
+	glfwPollEvents();
+}
+
+void set_buzzer_state(int state){
+	buzzer_state = state;
+}