draw mix texture

.gitignore

@@ -0,0 +1,2 @@
+*.out
+*~

build.sh

@@ -0,0 +1,9 @@
+set -eux
+
+CFLAGS="-Wall -Werror -Wfatal-errors -g -Og -std=gnu23 -Iinclude $(pkg-config --libs --cflags glfw3) -lm"
+
+if [ -f src/glad.o ]; then
+    gcc $CFLAGS src/main.c src/glad.o
+else
+    gcc $CFLAGS src/main.c src/glad.c
+fi

include/KHR/khrplatform.h

@@ -0,0 +1,311 @@
+#ifndef __khrplatform_h_
+#define __khrplatform_h_
+
+/*
+** Copyright (c) 2008-2018 The Khronos Group Inc.
+**
+** Permission is hereby granted, free of charge, to any person obtaining a
+** copy of this software and/or associated documentation files (the
+** "Materials"), to deal in the Materials without restriction, including
+** without limitation the rights to use, copy, modify, merge, publish,
+** distribute, sublicense, and/or sell copies of the Materials, and to
+** permit persons to whom the Materials are furnished to do so, subject to
+** the following conditions:
+**
+** The above copyright notice and this permission notice shall be included
+** in all copies or substantial portions of the Materials.
+**
+** THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+** EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+** MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+** IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+** CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+** MATERIALS OR THE USE OR OTHER DEALINGS IN THE MATERIALS.
+*/
+
+/* Khronos platform-specific types and definitions.
+ *
+ * The master copy of khrplatform.h is maintained in the Khronos EGL
+ * Registry repository at https://github.com/KhronosGroup/EGL-Registry
+ * The last semantic modification to khrplatform.h was at commit ID:
+ *      67a3e0864c2d75ea5287b9f3d2eb74a745936692
+ *
+ * Adopters may modify this file to suit their platform. Adopters are
+ * encouraged to submit platform specific modifications to the Khronos
+ * group so that they can be included in future versions of this file.
+ * Please submit changes by filing pull requests or issues on
+ * the EGL Registry repository linked above.
+ *
+ *
+ * See the Implementer's Guidelines for information about where this file
+ * should be located on your system and for more details of its use:
+ *    http://www.khronos.org/registry/implementers_guide.pdf
+ *
+ * This file should be included as
+ *        #include <KHR/khrplatform.h>
+ * by Khronos client API header files that use its types and defines.
+ *
+ * The types in khrplatform.h should only be used to define API-specific types.
+ *
+ * Types defined in khrplatform.h:
+ *    khronos_int8_t              signed   8  bit
+ *    khronos_uint8_t             unsigned 8  bit
+ *    khronos_int16_t             signed   16 bit
+ *    khronos_uint16_t            unsigned 16 bit
+ *    khronos_int32_t             signed   32 bit
+ *    khronos_uint32_t            unsigned 32 bit
+ *    khronos_int64_t             signed   64 bit
+ *    khronos_uint64_t            unsigned 64 bit
+ *    khronos_intptr_t            signed   same number of bits as a pointer
+ *    khronos_uintptr_t           unsigned same number of bits as a pointer
+ *    khronos_ssize_t             signed   size
+ *    khronos_usize_t             unsigned size
+ *    khronos_float_t             signed   32 bit floating point
+ *    khronos_time_ns_t           unsigned 64 bit time in nanoseconds
+ *    khronos_utime_nanoseconds_t unsigned time interval or absolute time in
+ *                                         nanoseconds
+ *    khronos_stime_nanoseconds_t signed time interval in nanoseconds
+ *    khronos_boolean_enum_t      enumerated boolean type. This should
+ *      only be used as a base type when a client API's boolean type is
+ *      an enum. Client APIs which use an integer or other type for
+ *      booleans cannot use this as the base type for their boolean.
+ *
+ * Tokens defined in khrplatform.h:
+ *
+ *    KHRONOS_FALSE, KHRONOS_TRUE Enumerated boolean false/true values.
+ *
+ *    KHRONOS_SUPPORT_INT64 is 1 if 64 bit integers are supported; otherwise 0.
+ *    KHRONOS_SUPPORT_FLOAT is 1 if floats are supported; otherwise 0.
+ *
+ * Calling convention macros defined in this file:
+ *    KHRONOS_APICALL
+ *    KHRONOS_APIENTRY
+ *    KHRONOS_APIATTRIBUTES
+ *
+ * These may be used in function prototypes as:
+ *
+ *      KHRONOS_APICALL void KHRONOS_APIENTRY funcname(
+ *                                  int arg1,
+ *                                  int arg2) KHRONOS_APIATTRIBUTES;
+ */
+
+#if defined(__SCITECH_SNAP__) && !defined(KHRONOS_STATIC)
+#   define KHRONOS_STATIC 1
+#endif
+
+/*-------------------------------------------------------------------------
+ * Definition of KHRONOS_APICALL
+ *-------------------------------------------------------------------------
+ * This precedes the return type of the function in the function prototype.
+ */
+#if defined(KHRONOS_STATIC)
+    /* If the preprocessor constant KHRONOS_STATIC is defined, make the
+     * header compatible with static linking. */
+#   define KHRONOS_APICALL
+#elif defined(_WIN32)
+#   define KHRONOS_APICALL __declspec(dllimport)
+#elif defined (__SYMBIAN32__)
+#   define KHRONOS_APICALL IMPORT_C
+#elif defined(__ANDROID__)
+#   define KHRONOS_APICALL __attribute__((visibility("default")))
+#else
+#   define KHRONOS_APICALL
+#endif
+
+/*-------------------------------------------------------------------------
+ * Definition of KHRONOS_APIENTRY
+ *-------------------------------------------------------------------------
+ * This follows the return type of the function  and precedes the function
+ * name in the function prototype.
+ */
+#if defined(_WIN32) && !defined(_WIN32_WCE) && !defined(__SCITECH_SNAP__)
+    /* Win32 but not WinCE */
+#   define KHRONOS_APIENTRY __stdcall
+#else
+#   define KHRONOS_APIENTRY
+#endif
+
+/*-------------------------------------------------------------------------
+ * Definition of KHRONOS_APIATTRIBUTES
+ *-------------------------------------------------------------------------
+ * This follows the closing parenthesis of the function prototype arguments.
+ */
+#if defined (__ARMCC_2__)
+#define KHRONOS_APIATTRIBUTES __softfp
+#else
+#define KHRONOS_APIATTRIBUTES
+#endif
+
+/*-------------------------------------------------------------------------
+ * basic type definitions
+ *-----------------------------------------------------------------------*/
+#if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L) || defined(__GNUC__) || defined(__SCO__) || defined(__USLC__)
+
+
+/*
+ * Using <stdint.h>
+ */
+#include <stdint.h>
+typedef int32_t                 khronos_int32_t;
+typedef uint32_t                khronos_uint32_t;
+typedef int64_t                 khronos_int64_t;
+typedef uint64_t                khronos_uint64_t;
+#define KHRONOS_SUPPORT_INT64   1
+#define KHRONOS_SUPPORT_FLOAT   1
+/*
+ * To support platform where unsigned long cannot be used interchangeably with
+ * inptr_t (e.g. CHERI-extended ISAs), we can use the stdint.h intptr_t.
+ * Ideally, we could just use (u)intptr_t everywhere, but this could result in
+ * ABI breakage if khronos_uintptr_t is changed from unsigned long to
+ * unsigned long long or similar (this results in different C++ name mangling).
+ * To avoid changes for existing platforms, we restrict usage of intptr_t to
+ * platforms where the size of a pointer is larger than the size of long.
+ */
+#if defined(__SIZEOF_LONG__) && defined(__SIZEOF_POINTER__)
+#if __SIZEOF_POINTER__ > __SIZEOF_LONG__
+#define KHRONOS_USE_INTPTR_T
+#endif
+#endif
+
+#elif defined(__VMS ) || defined(__sgi)
+
+/*
+ * Using <inttypes.h>
+ */
+#include <inttypes.h>
+typedef int32_t                 khronos_int32_t;
+typedef uint32_t                khronos_uint32_t;
+typedef int64_t                 khronos_int64_t;
+typedef uint64_t                khronos_uint64_t;
+#define KHRONOS_SUPPORT_INT64   1
+#define KHRONOS_SUPPORT_FLOAT   1
+
+#elif defined(_WIN32) && !defined(__SCITECH_SNAP__)
+
+/*
+ * Win32
+ */
+typedef __int32                 khronos_int32_t;
+typedef unsigned __int32        khronos_uint32_t;
+typedef __int64                 khronos_int64_t;
+typedef unsigned __int64        khronos_uint64_t;
+#define KHRONOS_SUPPORT_INT64   1
+#define KHRONOS_SUPPORT_FLOAT   1
+
+#elif defined(__sun__) || defined(__digital__)
+
+/*
+ * Sun or Digital
+ */
+typedef int                     khronos_int32_t;
+typedef unsigned int            khronos_uint32_t;
+#if defined(__arch64__) || defined(_LP64)
+typedef long int                khronos_int64_t;
+typedef unsigned long int       khronos_uint64_t;
+#else
+typedef long long int           khronos_int64_t;
+typedef unsigned long long int  khronos_uint64_t;
+#endif /* __arch64__ */
+#define KHRONOS_SUPPORT_INT64   1
+#define KHRONOS_SUPPORT_FLOAT   1
+
+#elif 0
+
+/*
+ * Hypothetical platform with no float or int64 support
+ */
+typedef int                     khronos_int32_t;
+typedef unsigned int            khronos_uint32_t;
+#define KHRONOS_SUPPORT_INT64   0
+#define KHRONOS_SUPPORT_FLOAT   0
+
+#else
+
+/*
+ * Generic fallback
+ */
+#include <stdint.h>
+typedef int32_t                 khronos_int32_t;
+typedef uint32_t                khronos_uint32_t;
+typedef int64_t                 khronos_int64_t;
+typedef uint64_t                khronos_uint64_t;
+#define KHRONOS_SUPPORT_INT64   1
+#define KHRONOS_SUPPORT_FLOAT   1
+
+#endif
+
+
+/*
+ * Types that are (so far) the same on all platforms
+ */
+typedef signed   char          khronos_int8_t;
+typedef unsigned char          khronos_uint8_t;
+typedef signed   short int     khronos_int16_t;
+typedef unsigned short int     khronos_uint16_t;
+
+/*
+ * Types that differ between LLP64 and LP64 architectures - in LLP64,
+ * pointers are 64 bits, but 'long' is still 32 bits. Win64 appears
+ * to be the only LLP64 architecture in current use.
+ */
+#ifdef KHRONOS_USE_INTPTR_T
+typedef intptr_t               khronos_intptr_t;
+typedef uintptr_t              khronos_uintptr_t;
+#elif defined(_WIN64)
+typedef signed   long long int khronos_intptr_t;
+typedef unsigned long long int khronos_uintptr_t;
+#else
+typedef signed   long  int     khronos_intptr_t;
+typedef unsigned long  int     khronos_uintptr_t;
+#endif
+
+#if defined(_WIN64)
+typedef signed   long long int khronos_ssize_t;
+typedef unsigned long long int khronos_usize_t;
+#else
+typedef signed   long  int     khronos_ssize_t;
+typedef unsigned long  int     khronos_usize_t;
+#endif
+
+#if KHRONOS_SUPPORT_FLOAT
+/*
+ * Float type
+ */
+typedef          float         khronos_float_t;
+#endif
+
+#if KHRONOS_SUPPORT_INT64
+/* Time types
+ *
+ * These types can be used to represent a time interval in nanoseconds or
+ * an absolute Unadjusted System Time.  Unadjusted System Time is the number
+ * of nanoseconds since some arbitrary system event (e.g. since the last
+ * time the system booted).  The Unadjusted System Time is an unsigned
+ * 64 bit value that wraps back to 0 every 584 years.  Time intervals
+ * may be either signed or unsigned.
+ */
+typedef khronos_uint64_t       khronos_utime_nanoseconds_t;
+typedef khronos_int64_t        khronos_stime_nanoseconds_t;
+#endif
+
+/*
+ * Dummy value used to pad enum types to 32 bits.
+ */
+#ifndef KHRONOS_MAX_ENUM
+#define KHRONOS_MAX_ENUM 0x7FFFFFFF
+#endif
+
+/*
+ * Enumerated boolean type
+ *
+ * Values other than zero should be considered to be true.  Therefore
+ * comparisons should not be made against KHRONOS_TRUE.
+ */
+typedef enum {
+    KHRONOS_FALSE = 0,
+    KHRONOS_TRUE  = 1,
+    KHRONOS_BOOLEAN_ENUM_FORCE_SIZE = KHRONOS_MAX_ENUM
+} khronos_boolean_enum_t;
+
+#endif /* __khrplatform_h_ */

src/main.c

@@ -0,0 +1,314 @@
+#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 <glad/glad.h>
+#include <GLFW/glfw3.h>
+
+void framebuffer_size_callback(GLFWwindow* window, int width, int height)
+{
+  glViewport(0, 0, width, height);
+}
+
+const char *vertexShaderSource = R"(
+#version 120
+
+attribute vec2 position;
+
+varying vec2 texcoord;
+
+void main()
+{
+  gl_Position = vec4(position, 0.0, 1.0);
+
+  vec2 tex = position * vec2(0.5) + vec2(0.5);
+
+  texcoord = vec2(tex.x * 400 / 512,
+                  (1.0 - tex.y) * 300 / 512);
+}
+  )"
+  ;
+
+const char *fragmentShaderSource = R"(
+#version 120
+
+uniform float fade_factor;
+uniform sampler2D textures[2];
+
+varying vec2 texcoord;
+
+void main()
+{
+  gl_FragColor = mix(texture2D(textures[0], texcoord),
+                     texture2D(textures[1], texcoord),
+                     fade_factor
+                     );
+}
+
+)"
+;
+
+unsigned int compile_shaders()
+{
+  unsigned int vertexShader;
+  vertexShader = glCreateShader(GL_VERTEX_SHADER);
+  glShaderSource(vertexShader, 1, &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);
+    }
+  }
+
+  unsigned int fragmentShader;
+  fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
+  glShaderSource(fragmentShader, 1, &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);
+    }
+  }
+
+  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[] = {
+  -1.0f, -1.0f,
+   1.0f, -1.0f,
+  -1.0f,  1.0f,
+   1.0f,  1.0f
+};
+
+static const unsigned short element_buffer_data[] = {
+  0, 1, 2, 3
+};
+
+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);
+
+  ssize_t read_size = read(fd, buf, size);
+  if (read_size == -1) {
+    fprintf(stderr, "read(%s): %s\n", filename, strerror(errno));
+    return NULL;
+  }
+
+  return buf;
+}
+
+static unsigned int make_texture(const char * filename)
+{
+  unsigned int texture;
+  int width = 512;
+  int height = 512;
+
+  void * pixels = read_file(filename);
+  if (!pixels)
+    return 0;
+
+  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_LINEAR);
+  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_RGBA8,
+               width, height, 0,
+               GL_RGBA, GL_UNSIGNED_BYTE,
+               pixels);
+  free(pixels);
+  return texture;
+}
+
+struct location {
+  struct {
+    unsigned int fade_factor;
+    unsigned int textures[2];
+  } uniform;
+  struct {
+    unsigned int position;
+  } attrib;
+};
+
+int main()
+{
+  glfwInit();
+  glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
+  glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 1);
+  //glfwWindowHint(GLFW_OPENGL_DEBUG_CONTEXT, GLFW_TRUE);
+
+  GLFWwindow* window = glfwCreateWindow(800, 600, "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);
+
+  if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
+    printf("Failed to initialize GLAD\n");
+    return -1;
+  }
+
+  glViewport(0, 0, 800, 600);
+  glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
+
+  unsigned int vertex_buffer = make_buffer(GL_ARRAY_BUFFER,
+                                           vertex_buffer_data,
+                                           (sizeof (vertex_buffer_data)));
+
+  unsigned int element_buffer = make_buffer(GL_ARRAY_BUFFER,
+                                            element_buffer_data,
+                                            (sizeof (element_buffer_data)));
+
+  unsigned int texture_0 = make_texture("texture/gl2-hello-1.data");
+  unsigned int texture_1 = make_texture("texture/gl2-hello-2.data");
+
+  unsigned int shaderProgram = compile_shaders();
+
+  struct location location;
+
+  location.uniform.fade_factor = glGetUniformLocation(shaderProgram, "fade_factor");
+  location.uniform.textures[0] = glGetUniformLocation(shaderProgram, "textures[0]");
+  location.uniform.textures[1] = glGetUniformLocation(shaderProgram, "textures[1]");
+
+  printf("uniforms:\n  fade_factor: %u\n  textures_0: %u\n  textures_1: %u\n",
+         location.uniform.fade_factor,
+         location.uniform.textures[0],
+         location.uniform.textures[1]);
+
+  location.attrib.position = glGetAttribLocation(shaderProgram, "position");
+  printf("attributes:\n  position %u\n",
+         location.attrib.position);
+
+  float fade_factor = 0;
+
+  struct timespec last;
+  struct timespec cur;
+
+  clock_gettime(CLOCK_MONOTONIC, &last);
+
+  while(!glfwWindowShouldClose(window)) {
+    if(glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
+      glfwSetWindowShouldClose(window, true);
+
+    glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
+    glClear(GL_COLOR_BUFFER_BIT);
+
+    //
+    // render
+    //
+    glUseProgram(shaderProgram);
+    glUniform1f(location.uniform.fade_factor, fade_factor);
+
+    glActiveTexture(GL_TEXTURE0);
+    glBindTexture(GL_TEXTURE_2D, texture_0);
+    glUniform1i(location.uniform.textures[0], 0);
+
+    glActiveTexture(GL_TEXTURE1);
+    glBindTexture(GL_TEXTURE_2D, texture_1);
+    glUniform1i(location.uniform.textures[1], 1);
+
+    glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer);
+    glVertexAttribPointer(location.attrib.position,
+                          2,
+                          GL_FLOAT,
+                          GL_FALSE,
+                          (sizeof (float)) * 2,
+                          (void*)0
+                          );
+    glEnableVertexAttribArray(location.attrib.position);
+
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, element_buffer);
+    glDrawElements(GL_TRIANGLE_STRIP,
+                   4,
+                   GL_UNSIGNED_SHORT,
+                   (void*)0
+                   );
+
+    glDisableVertexAttribArray(location.attrib.position);
+
+    glfwSwapBuffers(window);
+    glfwPollEvents();
+
+    clock_gettime(CLOCK_MONOTONIC, &cur);
+    uint64_t last_msec = (last.tv_sec * 1000) + (last.tv_nsec * 1e-06);
+    uint64_t cur_msec = (cur.tv_sec * 1000) + (cur.tv_nsec * 1e-06);
+    uint64_t dt = cur_msec - last_msec;
+    fade_factor = sin(dt * 0.001f) * 0.5 + 0.5;
+
+    //last = cur;
+  }
+
+  glfwTerminate();
+
+  return 0;
+}