add "shadertoy" template

src/shadertoy.c

@@ -0,0 +1,201 @@
+#include <fcntl.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <math.h>
+
+#include <GLFW/glfw3.h>
+#include <GLES2/gl2.h>
+
+static void * read_file(const char * filename)
+{
+  int fd = open(filename, O_RDONLY);
+  if (fd == -1) {
+    fprintf(stderr, "open(%s): %s\n", filename, strerror(errno));
+    return NULL;
+  }
+
+  off_t size = lseek(fd, 0, SEEK_END);
+  if (size == (off_t)-1) {
+    fprintf(stderr, "lseek(%s, SEEK_END): %s\n", filename, strerror(errno));
+    return NULL;
+  }
+
+  off_t start = lseek(fd, 0, SEEK_SET);
+  if (start == (off_t)-1) {
+    fprintf(stderr, "lseek(%s, SEEK_SET): %s\n", filename, strerror(errno));
+    return NULL;
+  }
+
+  void * buf = malloc(size+1);
+
+  ssize_t read_size = read(fd, buf, size);
+  if (read_size == -1) {
+    fprintf(stderr, "read(%s): %s\n", filename, strerror(errno));
+    return NULL;
+  }
+  ((char*)buf)[read_size] = 0;
+
+  return buf;
+}
+
+void framebuffer_size_callback(GLFWwindow* window, int width, int height)
+{
+  glViewport(0, 0, width, height);
+}
+
+unsigned int compile_shaders()
+{
+  void * vertexShaderSource = read_file("src/shadertoy.vp.glsl");
+  unsigned int vertexShader;
+  vertexShader = glCreateShader(GL_VERTEX_SHADER);
+  glShaderSource(vertexShader, 1, (const char **)&vertexShaderSource, NULL);
+  glCompileShader(vertexShader);
+  {
+    int  success;
+    char infoLog[512];
+    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
+    if(!success) {
+      glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
+      printf("vertex shader compile failed:\n%s\n", infoLog);
+    }
+  }
+  free(vertexShaderSource);
+
+  void * fragmentShaderSource = read_file("src/shadertoy.fp.glsl");
+  unsigned int fragmentShader;
+  fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
+  glShaderSource(fragmentShader, 1, (const char **)&fragmentShaderSource, NULL);
+  glCompileShader(fragmentShader);
+  {
+    int  success;
+    char infoLog[512];
+    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
+    if(!success) {
+      glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
+      printf("fragment shader compile failed:\n%s\n", infoLog);
+    }
+  }
+  free(fragmentShaderSource);
+
+  unsigned int shaderProgram;
+  shaderProgram = glCreateProgram();
+
+  glAttachShader(shaderProgram, vertexShader);
+  glAttachShader(shaderProgram, fragmentShader);
+  glLinkProgram(shaderProgram);
+
+  {
+    int  success;
+    char infoLog[512];
+    glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
+    if(!success) {
+      glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
+      printf("program link failed:\n%s\n", infoLog);
+    }
+  }
+
+  glDeleteShader(vertexShader);
+  glDeleteShader(fragmentShader);
+
+  return shaderProgram;
+}
+
+static int make_buffer(unsigned int target,
+                       const void * data,
+                       size_t size)
+{
+  unsigned int buffer;
+  glGenBuffers(1, &buffer);
+  glBindBuffer(target, buffer);
+  glBufferData(target, size, data, GL_STATIC_DRAW);
+  return buffer;
+}
+
+static const float vertex_buffer_data[] = {
+  // position
+  -1.0f, -1.0f, 0.0f,
+   1.0f, -1.0f, 0.0f,
+   1.0f,  1.0f, 0.0f,
+
+  -1.0f, -1.0f, 0.0f,
+   1.0f,  1.0f, 0.0f,
+  -1.0f,  1.0f, 0.0f
+};
+
+struct location {
+  struct {
+    unsigned int position;
+  } attrib;
+};
+
+int main()
+{
+  glfwInitHint(GLFW_PLATFORM, GLFW_PLATFORM_X11);
+  glfwInit();
+  glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
+  glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 1);
+  //glfwWindowHint(GLFW_OPENGL_DEBUG_CONTEXT, GLFW_TRUE);
+
+  GLFWwindow* window = glfwCreateWindow(1200, 1200, "LearnOpenGL", NULL, NULL);
+  if (window == NULL) {
+    const char* description;
+    glfwGetError(&description);
+    printf("Failed to create GLFW window: %s\n", description);
+    glfwTerminate();
+    return -1;
+  }
+  glfwMakeContextCurrent(window);
+
+  glViewport(0, 0, 1200, 1200);
+  //glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
+
+  unsigned int vertex_buffer = make_buffer(GL_ARRAY_BUFFER,
+                                           vertex_buffer_data,
+                                           (sizeof (vertex_buffer_data)));
+
+  printf("compile start\n");
+  unsigned int shaderProgram = compile_shaders();
+  printf("compile end\n");
+
+  struct location location;
+
+  location.attrib.position = glGetAttribLocation(shaderProgram, "position");
+  printf("attributes:\n  position %u\n",
+         location.attrib.position);
+
+  while(!glfwWindowShouldClose(window)) {
+    if(glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
+      glfwSetWindowShouldClose(window, true);
+
+    //glClearColor(0.1f, 0.1f, 0.1f, 0.1f);
+    //glClear(GL_COLOR_BUFFER_BIT);
+
+    //
+    // render
+    //
+    glUseProgram(shaderProgram);
+
+    glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer);
+    glVertexAttribPointer(location.attrib.position,
+                          3,
+                          GL_FLOAT,
+                          GL_FALSE,
+                          (sizeof (float)) * 3,
+                          (void*)0
+                          );
+    glEnableVertexAttribArray(location.attrib.position);
+
+    glDrawArrays(GL_TRIANGLES, 0, 6);
+
+    glfwSwapBuffers(window);
+    glfwPollEvents();
+  }
+
+  glfwTerminate();
+
+  return 0;
+}

src/shadertoy.fp.glsl

@@ -0,0 +1,8 @@
+#version 120
+
+varying vec2 pos_out;
+
+void main()
+{
+  gl_FragColor = vec4(pos_out, 0, 1);
+}

src/shadertoy.vp.glsl

@@ -0,0 +1,11 @@
+#version 120
+
+attribute vec3 position;
+
+varying vec2 pos_out;
+
+void main()
+{
+  gl_Position = vec4(position, 1);
+  pos_out = vec2(position);
+}

src/texture_cube_depth_vertex_shader.c

@@ -134,7 +134,8 @@ struct location {
   } attrib;
   struct {
     unsigned int texture1;
-    unsigned int theta;
+    unsigned int theta1;
+    unsigned int theta2;
   } uniform;
 };
 
@@ -187,26 +188,6 @@ const face faces[] = {
   {5,1}, {1,4}, {2,2},
 };
 
-static inline vec3 rotate(vec3 vertex, float theta)
-{
-  float x = vertex.x;
-  float y = vertex.y;
-  float z = vertex.z;
-  float t;
-
-  t  = y * cosf(theta) - z * sinf(theta);
-  z  = y * sinf(theta) + z * cosf(theta);
-  y  = t;
-
-  float theta2 = 3.14 * sinf(theta / 2);
-
-  t  = x * cosf(theta2) - z * sinf(theta2);
-  z  = x * sinf(theta2) + z * cosf(theta2);
-  x  = t;
-
-  return (vec3){x, y, z};
-}
-
 int main()
 {
   glfwInitHint(GLFW_PLATFORM, GLFW_PLATFORM_X11);
@@ -265,10 +246,12 @@ int main()
          location.attrib.texture);
 
   location.uniform.texture1 = glGetUniformLocation(shaderProgram, "texture1");
-  location.uniform.theta = glGetUniformLocation(shaderProgram, "theta");
-  printf("uniforms:\n  texture %u\n  theta %u\n",
+  location.uniform.theta1 = glGetUniformLocation(shaderProgram, "theta1");
+  location.uniform.theta2 = glGetUniformLocation(shaderProgram, "theta2");
+  printf("uniforms:\n  texture %u\n  theta1 %u\n  theta2 %u\n",
          location.uniform.texture1,
-         location.uniform.theta);
+         location.uniform.theta1,
+         location.uniform.theta2);
 
   unsigned int texture1;
   glGenTextures(1, &texture1);
@@ -290,7 +273,7 @@ int main()
       glfwSetWindowShouldClose(window, true);
 
     glClearDepthf(-1000.0f);
-    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+    //glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
     glDepthFunc(GL_GREATER);
     glEnable(GL_DEPTH_TEST);
 
@@ -318,7 +301,8 @@ int main()
     glEnableVertexAttribArray(location.attrib.position);
     glEnableVertexAttribArray(location.attrib.texture);
 
-    glUniform1f(location.uniform.theta, theta);
+    glUniform1f(location.uniform.theta1, theta);
+    glUniform1f(location.uniform.theta2, 3.14 * sin(theta / 2));
     theta += 0.005f;
 
     glUniform1i(location.uniform.texture1, 0);

src/texture_cube_depth_vertex_shader.vp.glsl

@@ -3,23 +3,28 @@
 attribute vec3 pos;
 attribute vec2 tex;
 
-uniform float theta;
+uniform float theta1;
+uniform float theta2;
 
 vec3 rotate(vec3 v)
 {
-  float x = v.x;
-  float y = v.y;
-  float z = v.z;
+  float ct1 = cos(theta1);
+  float st1 = sin(theta1);
 
-  float x1 = x;
-  float y1 = y * cos(theta) - z * sin(theta);
-  float z1 = y * sin(theta) + z * cos(theta);
+  float ct2 = cos(theta2);
+  float st2 = sin(theta2);
 
-  float theta2 = 3.14 * sin(theta / 2);
+  float x0 = v.x;
+  float y0 = v.y;
+  float z0 = v.z;
 
-  float x2 = x1 * cos(theta2) - z1 * sin(theta2);
+  float x1 = x0;
+  float y1 = y0 * ct1 - z0 * st1;
+  float z1 = y0 * st1 + z0 * ct1;
+
+  float x2 = x1 * ct2 - z1 * st2;
   float y2 = y1;
-  float z2 = x1 * sin(theta2) + z1 * cos(theta2);
+  float z2 = x1 * st2 + z1 * ct2;
 
   return vec3(x2 * 0.2,
               y2 * 0.2,

src/vertex_color.c

@@ -131,6 +131,7 @@ struct location {
 
 int main()
 {
+  glfwInitHint(GLFW_PLATFORM, GLFW_PLATFORM_X11);
   glfwInit();
   glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
   glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 1);

src/vertex_color.vp.glsl

@@ -3,8 +3,6 @@
 attribute vec3 position;
 attribute vec3 color;
 
-//varying vec3 color_out;
-
 void main()
 {
   gl_Position = vec4(position, 1);