OpenSubdiv/examples/common/glUtils.cpp
2015-06-03 18:36:08 -07:00

299 lines
8.1 KiB
C++

//
// Copyright 2015 Pixar
//
// Licensed under the Apache License, Version 2.0 (the "Apache License")
// with the following modification; you may not use this file except in
// compliance with the Apache License and the following modification to it:
// Section 6. Trademarks. is deleted and replaced with:
//
// 6. Trademarks. This License does not grant permission to use the trade
// names, trademarks, service marks, or product names of the Licensor
// and its affiliates, except as required to comply with Section 4(c) of
// the License and to reproduce the content of the NOTICE file.
//
// You may obtain a copy of the Apache License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the Apache License with the above modification is
// distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the Apache License for the specific
// language governing permissions and limitations under the Apache License.
//
#include <sstream>
#include <string>
#include <cstring>
#include <vector>
#include "glUtils.h"
#define STB_IMAGE_WRITE_IMPLEMENTATION 1
#include "stb_image_write.h"
#include <GLFW/glfw3.h>
#if _MSC_VER
#define snprintf _snprintf
#endif
namespace GLUtils {
// Note that glewIsSupported is required here for Core profile, glewGetExtension
// and GLEW_extension_name will not work on all drivers.
#ifdef OSD_USES_GLEW
#define IS_SUPPORTED(x) \
(glewIsSupported(x) == GL_TRUE)
#endif
static void
_argParseBool(bool *ret, const char *lbl, int i, int argc, char **argv)
{
if (i < argc-1) {
if (!strcmp(argv[i+1], "on")) {
*ret = true;
} else if (!strcmp(argv[i+1], "off")) {
*ret = false;
} else {
fprintf(stderr, "Unknown setting for %s: %s\n", lbl, argv[i+1]);
exit(1);
}
} else {
fprintf(stderr,
"Please specify \"on\" or \"off\" for %s.\n", lbl);
exit(1);
}
}
void
SetMinimumGLVersion(int argc, char ** argv) {
#if defined(__APPLE__)
// Here 3.2 is the minimum GL version supported, GLFW will allocate a
// higher version if possible. This works on OS X, but instead limits
// the version to 3.2 on Linux. On Linux & Windows, specifying no
// version hint should use the highest version available.
//
// http://www.glfw.org/faq.html#how-do-i-create-an-opengl-30-context
// http://www.glfw.org/faq.html#what-versions-of-opengl-are-supported-by-glfw
bool coreProfile = true;
bool forwardCompat = true;
bool versionSet = true;
int major = 3;
int minor = 2;
#else
bool coreProfile = false;
bool forwardCompat = false;
bool versionSet = false;
int major = 4;
int minor = 2;
#endif
for (int i = 1; i < argc; ++i) {
if (!strcmp(argv[i], "-glCoreProfile")) {
_argParseBool(&coreProfile, argv[i], i, argc, argv);
}
if (!strcmp(argv[i], "-glForwardCompat")) {
_argParseBool(&forwardCompat, argv[i], i, argc, argv);
}
if (!strcmp(argv[i], "-glVersion")) {
if (i < argc-1) {
char *versionStr = argv[i+1];
size_t len = strlen(versionStr);
if (len == 3 && versionStr[1] == '.' &&
versionStr[0] >= '0' && versionStr[0] <= '9' &&
versionStr[2] >= '0' && versionStr[2] <= '9') {
major = versionStr[0] - '0';
minor = versionStr[2] - '0';
versionSet = true;
} else {
fprintf(stderr,
"Invalid version number: %s, please specify a number "
"in the format M.n, e.g., -glVersion 4.2.\n",
versionStr);
exit(1);
}
} else {
fprintf(stderr,
"Please specify a version number for glVersion "
"in the form M.n, e.g., -glVersion 4.2.\n");
exit(1);
}
}
}
#ifdef CORE_PROFILE
if (coreProfile) {
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
}
if (forwardCompat) {
glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
}
#endif
if (versionSet) {
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, major);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, minor);
}
}
void
PrintGLVersion() {
std::cout << glGetString(GL_VENDOR) << "\n";
std::cout << glGetString(GL_RENDERER) << "\n";
std::cout << glGetString(GL_VERSION) << "\n";
int i;
std::cout << "Init OpenGL ";
glGetIntegerv(GL_MAJOR_VERSION, &i);
std::cout << i << ".";
glGetIntegerv(GL_MINOR_VERSION, &i);
std::cout << i << "\n";
}
void
CheckGLErrors(std::string const & where) {
GLuint err;
while ((err = glGetError()) != GL_NO_ERROR) {
std::cerr << "GL error: "
<< (where.empty() ? "" : where + " ")
<< err << "\n";
}
}
GLuint
CompileShader(GLenum shaderType, const char *source) {
GLuint shader = glCreateShader(shaderType);
glShaderSource(shader, 1, &source, NULL);
glCompileShader(shader);
GLint status;
glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
if (status == GL_FALSE) {
GLchar emsg[40960];
glGetShaderInfoLog(shader, sizeof(emsg), 0, emsg);
fprintf(stderr, "Error compiling GLSL shader: %s\n", emsg);
return 0;
}
return shader;
}
void
WriteScreenshot(int width, int height) {
std::vector<unsigned char> data(width*height*4 /*RGBA*/);
glPixelStorei(GL_PACK_ALIGNMENT, 1);
glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, &data[0]);
static int counter=0;
char fname[64];
snprintf(fname, 64, "screenshot.%d.png", counter++);
// flip vertical
stbi_write_png(fname, width, height, 4, &data[width*4*(height-1)], -width*4);
fprintf(stdout, "Saved %s\n", fname);
}
bool
SupportsAdaptiveTessellation() {
#ifdef OSD_USES_GLEW
return IS_SUPPORTED("GL_ARB_tessellation_shader");
#else
#if defined(GL_ARB_tessellation_shader) || defined(GL_VERSION_4_0)
return true;
#else
return false;
#endif
#endif
}
void GetMajorMinorVersion(int *major, int *minor){
const GLubyte *ver = glGetString(GL_SHADING_LANGUAGE_VERSION);
if (!ver){
*major = -1;
*minor = -1;
}
else{
std::stringstream ss;
ss << std::string(ver, ver + 1) << " " << std::string(ver + 2, ver + 3);
ss >> *major;
ss >> *minor;
}
}
std::string
GetShaderVersion(){
std::string shader_version;
int major, minor;
GetMajorMinorVersion(&major, &minor);
int version_number = major * 10 + minor;
switch (version_number){
case 20:
shader_version = "110";
break;
case 21:
shader_version = "120";
break;
case 30:
shader_version = "130";
break;
case 31:
shader_version = "140";
break;
case 32:
shader_version = "150";
break;
default:
std::stringstream ss;
ss << version_number;
shader_version = ss.str() + "0";
break;
}
return shader_version;
}
/* Generates the version defintion needed by the glsl shaders based on the
* opengl string
*/
std::string GetShaderVersionInclude(){
return "#version " + GetShaderVersion() + "\n";
}
bool GL_ARBSeparateShaderObjectsOrGL_VERSION_4_1(){
#if defined(OSD_USES_GLEW)
return IS_SUPPORTED("GL_ARB_separate_shader_objects") ||
(GLEW_VERSION_4_1 && IS_SUPPORTED("GL_ARB_tessellation_shader"));
#else
#if defined(GL_ARB_separate_shader_objects) || defined(GL_VERSION_4_1)
return true;
#else
return false;
#endif
#endif
}
bool GL_ARBComputeShaderOrGL_VERSION_4_3() {
#if defined(OSD_USES_GLEW)
return IS_SUPPORTED("GL_ARB_compute_shader") ||
(GLEW_VERSION_4_3);
#else
#if defined(GL_ARB_compute_shader) || defined(GL_VERSION_4_3)
return true;
#else
return false;
#endif
#endif
}
#undef IS_SUPPORTED
} // namesapce GLUtils