first commit

Makefile

@@ -0,0 +1,27 @@
+.PHONY: all clean run
+VERSION = 0.0.1
+
+LIBS = sdl2 glew
+CMACRO = -DVERSION=\"$(VERSION)\"
+
+CC = gcc
+CFLAGS = -g -Wall -Wextra -pedantic $(shell pkg-config $(LIBS) --cflags) $(CMACRO)
+LDFLAGS = $(shell pkg-config $(LIBS) --libs) -lm
+
+all: zoomer 
+
+zoomer: zoomer.o
+	$(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS)
+
+%.o: %.c
+	$(CC) $(CFLAGS) -c -o $@ $<
+
+clean: 
+	rm -f *.o
+	rm -f zoomer 
+
+bear: clean
+	bear -- make
+
+run: zoomer 
+	./$<

fshader.glsl

@@ -0,0 +1,15 @@
+#version 420 core
+
+out vec4 FragColor;
+
+in vec2 TexPos;
+
+uniform sampler2D screenshot;
+uniform vec2 mousePos;
+
+void main(){
+	FragColor = texture(screenshot, TexPos);
+	if(distance(gl_FragCoord, vec4(mousePos, 0, 0)) <= 30){
+		FragColor = mix(FragColor, vec4(1., 1., 1., 1.), 0.5);
+	}
+}

tutils.h

@@ -0,0 +1,45 @@
+#pragma once
+#include <stdio.h>
+#include <stdlib.h>
+
+const char* pullArg(int *argc, char** argv[]){
+	if(*argc <= 0)
+		return NULL;
+	(*argc)--;
+	return *argv[0]++;
+}
+
+const char *readFile(const char* filename){
+	FILE *fd = fopen(filename, "r");
+	
+	fseek(fd, 0, SEEK_END);
+	long size = ftell(fd);
+	rewind(fd);
+
+	char* ret = malloc(size+1);
+	fread(ret, sizeof(char), size, fd);
+	ret[size] = 0;
+	return ret;
+}
+
+int codeChk(int code, const char* context, const char* error(void)){
+	if(code != 0){
+		if(error != NULL)
+			printf("[%s] -> %s \n", context, error());
+		else
+			printf("[%s]\n", context);
+		exit(0);
+	}
+	return code;
+}
+
+void* ptrChk(void* ptr, const char* context, const char* error(void)){
+	if(ptr == NULL){
+		if(error != NULL)
+			printf("[%s] -> %s \n", context, error());
+		else
+			printf("[%s]\n", context);
+		exit(0);
+	}
+	return ptr;
+}

vshader.glsl

@@ -0,0 +1,21 @@
+#version 420 core
+
+out vec2 TexPos;
+
+layout (location = 0) in vec2 aPos;
+layout (location = 1) in vec2 texPos;
+
+uniform vec2 camPos;
+uniform int zoom;
+
+float invLerp( float a, float b, float v ){
+	return (v - a) / (b - a);
+}
+
+void main(){
+	gl_Position = vec4(
+					(aPos + vec2(camPos.x, -camPos.y) * 2) * (invLerp(-10, 10, zoom) * 2),
+ 					0.0,
+					1.0) ;
+	TexPos = texPos;
+}

zoomer.c

@@ -0,0 +1,178 @@
+#include <SDL2/SDL.h>
+#include <GL/glew.h>
+
+#include "SDL_events.h"
+#include "SDL_mouse.h"
+#include "SDL_video.h"
+#include "tutils.h"
+
+#define STB_IMAGE_IMPLEMENTATION
+#include "stb_image.h"
+SDL_Window *w;
+SDL_Renderer *r;
+
+void shaderCheck(GLuint shader, const char* type){
+	GLint status;
+	glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
+	if(status == GL_FALSE){
+		char msg[1024];
+		glGetShaderInfoLog(shader, 1024, NULL, msg);
+		printf("SHADER ERROR (%s): %s\n",type, msg);
+	}
+}
+
+void programCheck(GLuint prog){
+	GLint status;
+	glGetProgramiv(prog, GL_LINK_STATUS, &status);
+	if(status == GL_FALSE){
+		char msg[1024];
+		glGetProgramInfoLog(prog, 1024, NULL, msg);
+		printf("LINKING ERROR: %s\n", msg);
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	const char *ProgramName = pullArg(&argc, &argv);
+
+	// TODO <tonitch>: Handle arguments
+	const char *c;
+	while ( (c = pullArg(&argc, &argv)) )
+		printf("%s\n", c);
+
+	//Screenshot
+	char *screenFile, *command;
+	asprintf(&screenFile, "/tmp/zoomer.png");
+	asprintf(&command, "scrot -oF %s", screenFile);
+	system(command);
+
+	int width, height, chan;
+	stbi_set_flip_vertically_on_load(1);
+	unsigned char *data = stbi_load(screenFile, &width, &height, &chan, 0);
+
+	// TODO <tonitch>: screenshot using X11 
+
+	codeChk(SDL_Init(SDL_INIT_VIDEO), "Can't initialize SDL", SDL_GetError);
+
+	w = SDL_CreateWindow(ProgramName, 0, 0, width, height, SDL_WINDOW_OPENGL);
+	r = SDL_CreateRenderer(w, -1, SDL_RENDERER_PRESENTVSYNC);
+	SDL_ShowCursor(SDL_DISABLE);
+
+	glewInit();
+
+	SDL_GL_SetAttribute(GL_MAJOR_VERSION, 4);
+	SDL_GL_SetAttribute(GL_MINOR_VERSION, 2);
+	SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
+	SDL_GLContext *glctx = SDL_GL_CreateContext(w);
+
+	GLuint vshader = glCreateShader(GL_VERTEX_SHADER),
+		   fshader = glCreateShader(GL_FRAGMENT_SHADER);
+	const char *vshadersrc = readFile("vshader.glsl"),
+			   *fshadersrc = readFile("fshader.glsl");
+
+	glShaderSource(vshader, 1, &vshadersrc, NULL);
+	glShaderSource(fshader, 1, &fshadersrc, NULL);
+
+	glCompileShader(vshader);
+	glCompileShader(fshader);
+	shaderCheck(vshader, "VERTEX");
+	shaderCheck(vshader, "FRAGMENT");
+
+	GLuint VBO, VAO, EBO;
+	glGenVertexArrays(1, &VAO);
+	glBindVertexArray(VAO);
+
+	const GLfloat points[] = {
+		-1.,  1.,		0., 1.,
+		 1.,  1.,		1., 1.,
+		 1., -1.,		1., 0.,
+		-1., -1.,		0., 0.,
+	};
+	const GLint tri[] = {
+		0, 1, 2,
+		0, 2, 3
+	};
+	glGenBuffers(1, &VBO);
+	glBindBuffer(GL_ARRAY_BUFFER, VBO);
+	glBufferData(GL_ARRAY_BUFFER, sizeof(points), points, GL_STATIC_DRAW);
+	glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(GLfloat)*4, 0);
+	glEnableVertexAttribArray(0);
+
+	glBufferData(GL_ARRAY_BUFFER, sizeof(points), points, GL_STATIC_DRAW);
+	glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(GLfloat)*4, (void*)(sizeof(GLfloat)*2));
+	glEnableVertexAttribArray(1);
+
+	glGenBuffers(1, &EBO);
+	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
+	glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(tri), tri, GL_STATIC_DRAW);
+
+	GLuint pshader = glCreateProgram();
+	glAttachShader(pshader, vshader);
+	glAttachShader(pshader, fshader);
+	glLinkProgram(pshader);
+	programCheck(pshader);
+
+	glUseProgram(pshader);
+
+	GLuint screenshotTexture;
+	glGenTextures(1, &screenshotTexture);
+	glBindTexture(GL_TEXTURE_2D, screenshotTexture);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
+	glGenerateMipmap(GL_TEXTURE_2D);
+	glActiveTexture(GL_TEXTURE0);
+	glBindTexture(GL_TEXTURE_2D, screenshotTexture);
+
+	int shouldClose = 0;
+	SDL_Event e;
+	float camPos[2] = {0.};
+	float mousePos[2] = {0.};
+	int zoom = 0;
+	int tick = 0;
+	while(!shouldClose){
+		while(SDL_PollEvent(&e)){
+			switch(e.type){
+				case SDL_QUIT:
+					shouldClose = 1;
+					break;
+				case SDL_KEYDOWN:
+					if(e.key.keysym.sym == SDLK_q)
+						shouldClose=1;
+					break;
+				case SDL_WINDOWEVENT:
+					if(e.window.event == SDL_WINDOWEVENT_RESIZED)
+						glViewport(0, 0, e.window.data1, e.window.data2);
+					break;
+				case SDL_MOUSEMOTION:;
+					int sw, sh;
+					SDL_GetWindowSize(w, &sw, &sh);
+					mousePos[0] = e.motion.x;
+					mousePos[1] = sh - e.motion.y;
+					if(e.motion.state & SDL_BUTTON_LMASK){
+						camPos[0] += e.motion.xrel / (float)sw;
+						camPos[1] += e.motion.yrel / (float)sh;
+					}
+					break;
+				case SDL_MOUSEWHEEL:
+					zoom += e.wheel.y;
+					break;
+			}
+		}
+		glClearColor(0., 0., 0., 1.);
+		glClear(GL_COLOR_BUFFER_BIT);
+		glUniform2f(glGetUniformLocation(pshader, "camPos"), camPos[0], camPos[1]);
+		glUniform2f(glGetUniformLocation(pshader, "mousePos"), mousePos[0], mousePos[1]);
+		glUniform1i(glGetUniformLocation(pshader, "zoom"), zoom);
+		glUniform1i(glGetUniformLocation(pshader, "tick"), tick);
+		
+		glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
+		/* glDrawArrays(GL_TRIANGLES, 0, 3); */
+		SDL_GL_SwapWindow(w);
+		tick++;
+	}
+
+	SDL_GL_DeleteContext(glctx);
+	SDL_Quit();
+	return 0;
+}