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OpenGL2: Fallback to OpenGL ES if OpenGL fails
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@zturtleman @mgerhardy
zturtleman authored and mgerhardy committed Jun 9, 2024
1 parent a2da110 commit 265d9db
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Showing 3 changed files with 97 additions and 83 deletions.
171 changes: 92 additions & 79 deletions code/sdl/sdl_glimp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -51,7 +51,7 @@ cvar_t *r_allowSoftwareGL; // Don't abort out if a hardware visual can't be obta
cvar_t *r_allowResize; // make window resizable
cvar_t *r_centerWindow;
cvar_t *r_sdlDriver;
cvar_t *r_useOpenGLES;
cvar_t *r_preferOpenGLES;

int qglMajorVersion, qglMinorVersion;
int qglesMajorVersion, qglesMinorVersion;
Expand Down Expand Up @@ -376,6 +376,12 @@ GLimp_SetMode
===============
*/
static int GLimp_SetMode(int mode, qboolean fullscreen, qboolean noborder, qboolean fixedFunction) {
struct GLimp_ContextType {
int profileMask;
int majorVersion;
int minorVersion;
} contexts[3];
int numContexts, type;
const char *glstring;
int perChannelColorBits;
int colorBits, depthBits, stencilBits;
Expand Down Expand Up @@ -483,6 +489,47 @@ static int GLimp_SetMode(int mode, qboolean fullscreen, qboolean noborder, qbool

stencilBits = r_stencilbits->value;
samples = r_ext_multisample->value;
numContexts = 0;

if (!fixedFunction) {
int profileMask;
qboolean preferOpenGLES;

SDL_GL_ResetAttributes();
SDL_GL_GetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, &profileMask);

preferOpenGLES = (r_preferOpenGLES->integer == 1 ||
(r_preferOpenGLES->integer == -1 && profileMask == SDL_GL_CONTEXT_PROFILE_ES));

if (preferOpenGLES) {
contexts[numContexts].profileMask = SDL_GL_CONTEXT_PROFILE_ES;
contexts[numContexts].majorVersion = 2;
contexts[numContexts].minorVersion = 0;
numContexts++;
}

contexts[numContexts].profileMask = SDL_GL_CONTEXT_PROFILE_CORE;
contexts[numContexts].majorVersion = 3;
contexts[numContexts].minorVersion = 2;
numContexts++;

contexts[numContexts].profileMask = 0;
contexts[numContexts].majorVersion = 2;
contexts[numContexts].minorVersion = 0;
numContexts++;

if (!preferOpenGLES) {
contexts[numContexts].profileMask = SDL_GL_CONTEXT_PROFILE_ES;
contexts[numContexts].majorVersion = 2;
contexts[numContexts].minorVersion = 0;
numContexts++;
}
} else {
contexts[numContexts].profileMask = 0;
contexts[numContexts].majorVersion = 1;
contexts[numContexts].minorVersion = 1;
numContexts++;
}

for (i = 0; i < 16; i++) {
int testColorBits, testDepthBits, testStencilBits;
Expand Down Expand Up @@ -609,97 +656,63 @@ static int GLimp_SetMode(int mode, qboolean fullscreen, qboolean noborder, qbool

SDL_SetWindowIcon(SDL_window, icon);

if (!fixedFunction) {
int profileMask;

SDL_GL_GetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, &profileMask);

if (r_useOpenGLES->integer == 1 ||
(r_useOpenGLES->integer == -1 && profileMask == SDL_GL_CONTEXT_PROFILE_ES)) {
ri.Printf(PRINT_ALL, "Trying to get an OpenGL ES 2.0 context\n");
SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_ES);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);

SDL_glContext = SDL_GL_CreateContext(SDL_window);
if (!SDL_glContext) {
ri.Printf(PRINT_ALL, "SDL_GL_CreateContext failed: %s\n", SDL_GetError());
} else {
ri.Printf(PRINT_ALL, "SDL_GL_CreateContext succeeded.\n");

if (!GLimp_GetProcAddresses(fixedFunction)) {
ri.Printf(PRINT_ALL, "GLimp_GetProcAddresses() failed for OpenGL ES 2.0 context\n");
GLimp_ClearProcAddresses();
SDL_GL_DeleteContext(SDL_glContext);
SDL_glContext = NULL;
}
}
for (type = 0; type < numContexts; type++) {
char contextName[32];
switch (contexts[type].profileMask) {
default:
case 0:
Com_sprintf(contextName, sizeof(contextName), "OpenGL %d.%d", contexts[type].majorVersion,
contexts[type].minorVersion);
break;
case SDL_GL_CONTEXT_PROFILE_CORE:
Com_sprintf(contextName, sizeof(contextName), "OpenGL %d.%d Core", contexts[type].majorVersion,
contexts[type].minorVersion);
break;
case SDL_GL_CONTEXT_PROFILE_ES:
Com_sprintf(contextName, sizeof(contextName), "OpenGL ES %d.%d", contexts[type].majorVersion,
contexts[type].minorVersion);
break;
}
SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, contexts[type].profileMask);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, contexts[type].majorVersion);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, contexts[type].minorVersion);

SDL_glContext = SDL_GL_CreateContext(SDL_window);
if (!SDL_glContext) {
ri.Printf(PRINT_ALL, "Trying to get an OpenGL 3.2 core context\n");
SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
ri.Printf(PRINT_ALL, "SDL_GL_CreateContext() for %s context failed: %s\n", contextName, SDL_GetError());
continue;
}

SDL_glContext = SDL_GL_CreateContext(SDL_window);
if (!SDL_glContext) {
ri.Printf(PRINT_ALL, "SDL_GL_CreateContext failed: %s\n", SDL_GetError());
} else {
const char *renderer;
if (!GLimp_GetProcAddresses(fixedFunction)) {
ri.Printf(PRINT_ALL, "GLimp_GetProcAddresses() for %s context failed\n", contextName);
GLimp_ClearProcAddresses();
SDL_GL_DeleteContext(SDL_glContext);
SDL_glContext = NULL;
continue;
}

ri.Printf(PRINT_ALL, "SDL_GL_CreateContext succeeded.\n");
if (contexts[type].profileMask == SDL_GL_CONTEXT_PROFILE_CORE) {
const char *renderer;

if (GLimp_GetProcAddresses(fixedFunction)) {
renderer = (const char *)qglGetString(GL_RENDERER);
} else {
ri.Printf(PRINT_ALL, "GLimp_GetProcAddresses() failed for OpenGL 3.2 core context\n");
renderer = NULL;
}
renderer = (const char *)qglGetString(GL_RENDERER);

if (!renderer || strstr(renderer, "Software Renderer") || strstr(renderer, "Software Rasterizer")) {
if (renderer)
ri.Printf(PRINT_ALL, "GL_RENDERER is %s, rejecting context\n", renderer);
if (!renderer || strstr(renderer, "Software Renderer") || strstr(renderer, "Software Rasterizer")) {
ri.Printf(PRINT_ALL, "GL_RENDERER is %s, rejecting %s context\n", renderer, contextName);

GLimp_ClearProcAddresses();
SDL_GL_DeleteContext(SDL_glContext);
SDL_glContext = NULL;
}
GLimp_ClearProcAddresses();
SDL_GL_DeleteContext(SDL_glContext);
SDL_glContext = NULL;
continue;
}
}

if (!SDL_glContext) {
ri.Printf(PRINT_ALL, "Trying to get an OpenGL 2.0 context\n");

SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, 0);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
}
} else {
SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, 0);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 1);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 1);

SDL_glContext = NULL;
break;
}

if (!SDL_glContext) {
if ((SDL_glContext = SDL_GL_CreateContext(SDL_window)) == NULL) {
ri.Printf(PRINT_DEVELOPER, "SDL_GL_CreateContext failed: %s\n", SDL_GetError());
SDL_DestroyWindow(SDL_window);
SDL_window = NULL;
continue;
}

if (!GLimp_GetProcAddresses(fixedFunction)) {
ri.Printf(PRINT_ALL, "GLimp_GetProcAddresses() failed\n");
GLimp_ClearProcAddresses();
SDL_GL_DeleteContext(SDL_glContext);
SDL_glContext = NULL;
SDL_DestroyWindow(SDL_window);
SDL_window = NULL;
continue;
}
SDL_DestroyWindow(SDL_window);
SDL_window = NULL;
continue;
}

qglClearColor(0, 0, 0, 1);
Expand Down Expand Up @@ -932,7 +945,7 @@ void GLimp_Init(qboolean fixedFunction) {
r_sdlDriver = ri.Cvar_Get("r_sdlDriver", "", CVAR_ROM);
r_allowResize = ri.Cvar_Get("r_allowResize", "0", CVAR_ARCHIVE | CVAR_LATCH);
r_centerWindow = ri.Cvar_Get("r_centerWindow", "0", CVAR_ARCHIVE | CVAR_LATCH);
r_useOpenGLES = ri.Cvar_Get("r_useOpenGLES", "-1", CVAR_ARCHIVE | CVAR_LATCH);
r_preferOpenGLES = ri.Cvar_Get("r_preferOpenGLES", "-1", CVAR_ARCHIVE | CVAR_LATCH);

if (ri.Cvar_VariableIntegerValue("com_abnormalExit")) {
ri.Cvar_Set("r_mode", va("%d", R_MODE_FALLBACK));
Expand Down
7 changes: 4 additions & 3 deletions docs/ioq3-readme.md
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Original file line number Diff line number Diff line change
Expand Up @@ -151,11 +151,12 @@ embedded System-on-a-Chip and mobile platforms.

The opengl1 renderer does not have OpenGL ES support.

The `r_useOpenGLES` cvar controls whether to use OpenGL or OpenGL ES API.
Set to -1 for auto (default), 0 for OpenGL, and 1 for OpenGL ES. It should be
The opengl2 renderer will try both OpenGL and OpenGL ES APIs to find one that
works. The `r_preferOpenGLES` cvar controls which API to try first.
Set it to -1 for auto (default), 0 for OpenGL, and 1 for OpenGL ES. It should be
set using command line arguments:

ioquake3 +set cl_renderer opengl2 +set r_useOpenGLES 1
ioquake3 +set cl_renderer opengl2 +set r_preferOpenGLES 1


# Console
Expand Down
2 changes: 1 addition & 1 deletion docs/opengl2-readme.md
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Original file line number Diff line number Diff line change
Expand Up @@ -65,7 +65,7 @@ For Win32:

Cvars for API:

* `r_useOpenGLES` - This enables using OpenGL ES 2+.
* `r_preferOpenGLES` - This enables using OpenGL ES 2+.
Many features are not supported such as sun shadows and HDR.
1 - Use OpenGL ES.
0 - Use desktop OpenGL.
Expand Down

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