src/video/kmsdrm/SDL_kmsdrmopengles.c - third_party/sdl - Git at Google

 /*
   Simple DirectMedia Layer
   Copyright (C) 1997-2021 Sam Lantinga <slouken@libsdl.org>

   This software is provided 'as-is', without any express or implied
   warranty.  In no event will the authors be held liable for any damages
   arising from the use of this software.

   Permission is granted to anyone to use this software for any purpose,
   including commercial applications, and to alter it and redistribute it
   freely, subject to the following restrictions:

   1. The origin of this software must not be misrepresented; you must not
      claim that you wrote the original software. If you use this software
      in a product, an acknowledgment in the product documentation would be
      appreciated but is not required.
   2. Altered source versions must be plainly marked as such, and must not be
      misrepresented as being the original software.
   3. This notice may not be removed or altered from any source distribution.
 */

 #include "../../SDL_internal.h"

 #if SDL_VIDEO_DRIVER_KMSDRM

 #include "SDL_log.h"

 #include "SDL_kmsdrmvideo.h"
 #include "SDL_kmsdrmopengles.h"
 #include "SDL_kmsdrmdyn.h"
 #include <errno.h>

 #ifndef EGL_PLATFORM_GBM_MESA
 #define EGL_PLATFORM_GBM_MESA 0x31D7
 #endif

 /* EGL implementation of SDL OpenGL support */

 void
 KMSDRM_GLES_DefaultProfileConfig(_THIS, int *mask, int *major, int *minor)
 {
     /* if SDL was _also_ built with the Raspberry Pi driver (so we're
        definitely a Pi device), default to GLES2. */
 #if SDL_VIDEO_DRIVER_RPI
     *mask = SDL_GL_CONTEXT_PROFILE_ES;
     *major = 2;
     *minor = 0;
 #endif
 }

 int
 KMSDRM_GLES_LoadLibrary(_THIS, const char *path) {
     /* Just pretend you do this here, but don't do it until KMSDRM_CreateWindow(),
        where we do the same library load we would normally do here.
        because this gets called by SDL_CreateWindow() before KMSDR_CreateWindow(),
        so gbm dev isn't yet created when this is called, AND we can't alter the
        call order in SDL_CreateWindow(). */
 #if 0
     NativeDisplayType display = (NativeDisplayType)((SDL_VideoData *)_this->driverdata)->gbm_dev;
     return SDL_EGL_LoadLibrary(_this, path, display, EGL_PLATFORM_GBM_MESA);
 #endif
     return 0;
 }

 void
 KMSDRM_GLES_UnloadLibrary(_THIS) {
     /* As with KMSDRM_GLES_LoadLibrary(), we define our own "dummy" unloading function
        so we manually unload the library whenever we want. */
 }

 SDL_EGL_CreateContext_impl(KMSDRM)

 int KMSDRM_GLES_SetSwapInterval(_THIS, int interval) {

     if (!_this->egl_data) {
         return SDL_SetError("EGL not initialized");
     }

     if (interval == 0 || interval == 1) {
         _this->egl_data->egl_swapinterval = interval;
     } else {
         return SDL_SetError("Only swap intervals of 0 or 1 are supported");
     }

     return 0;
 }

 int
 KMSDRM_GLES_SwapWindow(_THIS, SDL_Window * window) {
     SDL_WindowData *windata = ((SDL_WindowData *) window->driverdata);
     SDL_DisplayData *dispdata = (SDL_DisplayData *) SDL_GetDisplayForWindow(window)->driverdata;
     SDL_VideoData *viddata = ((SDL_VideoData *)_this->driverdata);
     KMSDRM_FBInfo *fb_info;
     int ret = 0;

     /* Always wait for the previous issued flip before issing a new one,
        even if you do async flips. */
     uint32_t flip_flags = DRM_MODE_PAGE_FLIP_EVENT;

     /* Wait for confirmation that the next front buffer has been flipped, at which
        point the previous front buffer can be released */
     if (!KMSDRM_WaitPageflip(_this, windata)) {
         SDL_LogError(SDL_LOG_CATEGORY_VIDEO, "Wait for previous pageflip failed");
         return 0;
     }

     /* Release the previous front buffer */
     if (windata->bo) {
         KMSDRM_gbm_surface_release_buffer(windata->gs, windata->bo);
         windata->bo = NULL;
     }

     windata->bo = windata->next_bo;

     /* Mark a buffer to becume the next front buffer.
        This won't happen until pagelip completes. */
     if (!(_this->egl_data->eglSwapBuffers(_this->egl_data->egl_display,
                                            windata->egl_surface))) {
         SDL_LogError(SDL_LOG_CATEGORY_VIDEO, "eglSwapBuffers failed");
         return 0;
     }

     /* From the GBM surface, get the next BO to become the next front buffer,
        and lock it so it can't be allocated as a back buffer (to prevent EGL
        from drawing into it!) */
     windata->next_bo = KMSDRM_gbm_surface_lock_front_buffer(windata->gs);
     if (!windata->next_bo) {
         SDL_LogError(SDL_LOG_CATEGORY_VIDEO, "Could not lock front buffer on GBM surface");
         return 0;
     }

     /* Get an actual usable fb for the next front buffer. */
     fb_info = KMSDRM_FBFromBO(_this, windata->next_bo);
     if (!fb_info) {
         SDL_LogError(SDL_LOG_CATEGORY_VIDEO, "Could not get a framebuffer");
         return 0;
     }

     /* Do we have a modeset pending? If so, configure the new mode on the CRTC.
        Has to be done before next pageflip issues, so the buffer with the
        new size is big enough for preventing CRTC from reading out of bounds. */
     if (dispdata->modeset_pending) {

         ret = KMSDRM_drmModeSetCrtc(viddata->drm_fd,
           dispdata->crtc->crtc_id, fb_info->fb_id, 0, 0,
           &dispdata->connector->connector_id, 1, &dispdata->mode);

         dispdata->modeset_pending = SDL_FALSE;

         if (ret) {
             SDL_LogError(SDL_LOG_CATEGORY_VIDEO, "Could not set videomode on CRTC.");
             return 0;
         }

         /* It's OK to return now if we have done a drmModeSetCrtc(),
            it has done the pageflip and blocked until it was done. */
         return 1;
     }

     /* Issue pageflip on the next front buffer.
        Remember: drmModePageFlip() never blocks, it just issues the flip,
        which will be done during the next vblank, or immediately if
        we pass the DRM_MODE_PAGE_FLIP_ASYNC flag.
        Since calling drmModePageFlip() will return EBUSY if we call it
        without having completed the last issued flip, we must pass the
        DRM_MODE_PAGE_FLIP_ASYNC if we don't block on EGL (egl_swapinterval = 0).
        That makes it flip immediately, without waiting for the next vblank
        to do so, so even if we don't block on EGL, the flip will have completed
        when we get here again. */

     if (_this->egl_data->egl_swapinterval == 0 && viddata->async_pageflip_support) {
         flip_flags |= DRM_MODE_PAGE_FLIP_ASYNC;
     }

     ret = KMSDRM_drmModePageFlip(viddata->drm_fd, dispdata->crtc->crtc_id,
 	     fb_info->fb_id, flip_flags, &windata->waiting_for_flip);

     if (ret == 0) {
 	windata->waiting_for_flip = SDL_TRUE;
     } else {
 	SDL_LogError(SDL_LOG_CATEGORY_VIDEO, "Could not queue pageflip: %d", ret);
     }

     /* Wait immediately for vsync (as if we only had two buffers).
        Even if we are already doing a WaitPageflip at the begining of this
        function, this is NOT redundant because here we wait immediately
        after submitting the image to the screen, reducing lag, and if
        we have waited here, there won't be a pending pageflip so the
        WaitPageflip at the beggining of this function will be a no-op.
        Just leave it here and don't worry.
        Run your SDL2 program with "SDL_KMSDRM_DOUBLE_BUFFER=1 <program_name>"
        to enable this. */
     if (windata->double_buffer) {
 	if (!KMSDRM_WaitPageflip(_this, windata)) {
 	    SDL_LogError(SDL_LOG_CATEGORY_VIDEO, "Immediate wait for previous pageflip failed");
 	    return 0;
 	}
     }

     return 1;
 }

 SDL_EGL_MakeCurrent_impl(KMSDRM)

 #endif /* SDL_VIDEO_DRIVER_KMSDRM */

 /* vi: set ts=4 sw=4 expandtab: */
	/*
	Simple DirectMedia Layer
	Copyright (C) 1997-2021 Sam Lantinga <slouken@libsdl.org>

	This software is provided 'as-is', without any express or implied
	warranty. In no event will the authors be held liable for any damages
	arising from the use of this software.

	Permission is granted to anyone to use this software for any purpose,
	including commercial applications, and to alter it and redistribute it
	freely, subject to the following restrictions:

	1. The origin of this software must not be misrepresented; you must not
	claim that you wrote the original software. If you use this software
	in a product, an acknowledgment in the product documentation would be
	appreciated but is not required.
	2. Altered source versions must be plainly marked as such, and must not be
	misrepresented as being the original software.
	3. This notice may not be removed or altered from any source distribution.
	*/

	#include "../../SDL_internal.h"

	#if SDL_VIDEO_DRIVER_KMSDRM

	#include "SDL_log.h"

	#include "SDL_kmsdrmvideo.h"
	#include "SDL_kmsdrmopengles.h"
	#include "SDL_kmsdrmdyn.h"
	#include <errno.h>

	#ifndef EGL_PLATFORM_GBM_MESA
	#define EGL_PLATFORM_GBM_MESA 0x31D7
	#endif

	/* EGL implementation of SDL OpenGL support */

	void
	KMSDRM_GLES_DefaultProfileConfig(_THIS, int mask, int major, int *minor)
	{
	/* if SDL was _also_ built with the Raspberry Pi driver (so we're
	definitely a Pi device), default to GLES2. */
	#if SDL_VIDEO_DRIVER_RPI
	*mask = SDL_GL_CONTEXT_PROFILE_ES;
	*major = 2;
	*minor = 0;
	#endif
	}

	int
	KMSDRM_GLES_LoadLibrary(_THIS, const char *path) {
	/* Just pretend you do this here, but don't do it until KMSDRM_CreateWindow(),
	where we do the same library load we would normally do here.
	because this gets called by SDL_CreateWindow() before KMSDR_CreateWindow(),
	so gbm dev isn't yet created when this is called, AND we can't alter the
	call order in SDL_CreateWindow(). */
	#if 0
	NativeDisplayType display = (NativeDisplayType)((SDL_VideoData *)_this->driverdata)->gbm_dev;
	return SDL_EGL_LoadLibrary(_this, path, display, EGL_PLATFORM_GBM_MESA);
	#endif
	return 0;
	}

	void
	KMSDRM_GLES_UnloadLibrary(_THIS) {
	/* As with KMSDRM_GLES_LoadLibrary(), we define our own "dummy" unloading function
	so we manually unload the library whenever we want. */
	}

	SDL_EGL_CreateContext_impl(KMSDRM)

	int KMSDRM_GLES_SetSwapInterval(_THIS, int interval) {

	if (!_this->egl_data) {
	return SDL_SetError("EGL not initialized");
	}

	if (interval == 0 \|\| interval == 1) {
	_this->egl_data->egl_swapinterval = interval;
	} else {
	return SDL_SetError("Only swap intervals of 0 or 1 are supported");
	}

	return 0;
	}

	int
	KMSDRM_GLES_SwapWindow(_THIS, SDL_Window * window) {
	SDL_WindowData windata = ((SDL_WindowData ) window->driverdata);
	SDL_DisplayData dispdata = (SDL_DisplayData ) SDL_GetDisplayForWindow(window)->driverdata;
	SDL_VideoData viddata = ((SDL_VideoData )_this->driverdata);
	KMSDRM_FBInfo *fb_info;
	int ret = 0;

	/* Always wait for the previous issued flip before issing a new one,
	even if you do async flips. */
	uint32_t flip_flags = DRM_MODE_PAGE_FLIP_EVENT;

	/* Wait for confirmation that the next front buffer has been flipped, at which
	point the previous front buffer can be released */
	if (!KMSDRM_WaitPageflip(_this, windata)) {
	SDL_LogError(SDL_LOG_CATEGORY_VIDEO, "Wait for previous pageflip failed");
	return 0;
	}

	/* Release the previous front buffer */
	if (windata->bo) {
	KMSDRM_gbm_surface_release_buffer(windata->gs, windata->bo);
	windata->bo = NULL;
	}

	windata->bo = windata->next_bo;

	/* Mark a buffer to becume the next front buffer.
	This won't happen until pagelip completes. */
	if (!(_this->egl_data->eglSwapBuffers(_this->egl_data->egl_display,
	windata->egl_surface))) {
	SDL_LogError(SDL_LOG_CATEGORY_VIDEO, "eglSwapBuffers failed");
	return 0;
	}

	/* From the GBM surface, get the next BO to become the next front buffer,
	and lock it so it can't be allocated as a back buffer (to prevent EGL
	from drawing into it!) */
	windata->next_bo = KMSDRM_gbm_surface_lock_front_buffer(windata->gs);
	if (!windata->next_bo) {
	SDL_LogError(SDL_LOG_CATEGORY_VIDEO, "Could not lock front buffer on GBM surface");
	return 0;
	}

	/* Get an actual usable fb for the next front buffer. */
	fb_info = KMSDRM_FBFromBO(_this, windata->next_bo);
	if (!fb_info) {
	SDL_LogError(SDL_LOG_CATEGORY_VIDEO, "Could not get a framebuffer");
	return 0;
	}

	/* Do we have a modeset pending? If so, configure the new mode on the CRTC.
	Has to be done before next pageflip issues, so the buffer with the
	new size is big enough for preventing CRTC from reading out of bounds. */
	if (dispdata->modeset_pending) {

	ret = KMSDRM_drmModeSetCrtc(viddata->drm_fd,
	dispdata->crtc->crtc_id, fb_info->fb_id, 0, 0,
	&dispdata->connector->connector_id, 1, &dispdata->mode);

	dispdata->modeset_pending = SDL_FALSE;

	if (ret) {
	SDL_LogError(SDL_LOG_CATEGORY_VIDEO, "Could not set videomode on CRTC.");
	return 0;
	}

	/* It's OK to return now if we have done a drmModeSetCrtc(),
	it has done the pageflip and blocked until it was done. */
	return 1;
	}

	/* Issue pageflip on the next front buffer.
	Remember: drmModePageFlip() never blocks, it just issues the flip,
	which will be done during the next vblank, or immediately if
	we pass the DRM_MODE_PAGE_FLIP_ASYNC flag.
	Since calling drmModePageFlip() will return EBUSY if we call it
	without having completed the last issued flip, we must pass the
	DRM_MODE_PAGE_FLIP_ASYNC if we don't block on EGL (egl_swapinterval = 0).
	That makes it flip immediately, without waiting for the next vblank
	to do so, so even if we don't block on EGL, the flip will have completed
	when we get here again. */

	if (_this->egl_data->egl_swapinterval == 0 && viddata->async_pageflip_support) {
	flip_flags \|= DRM_MODE_PAGE_FLIP_ASYNC;
	}

	ret = KMSDRM_drmModePageFlip(viddata->drm_fd, dispdata->crtc->crtc_id,
	fb_info->fb_id, flip_flags, &windata->waiting_for_flip);

	if (ret == 0) {
	windata->waiting_for_flip = SDL_TRUE;
	} else {
	SDL_LogError(SDL_LOG_CATEGORY_VIDEO, "Could not queue pageflip: %d", ret);
	}

	/* Wait immediately for vsync (as if we only had two buffers).
	Even if we are already doing a WaitPageflip at the begining of this
	function, this is NOT redundant because here we wait immediately
	after submitting the image to the screen, reducing lag, and if
	we have waited here, there won't be a pending pageflip so the
	WaitPageflip at the beggining of this function will be a no-op.
	Just leave it here and don't worry.
	Run your SDL2 program with "SDL_KMSDRM_DOUBLE_BUFFER=1 <program_name>"
	to enable this. */
	if (windata->double_buffer) {
	if (!KMSDRM_WaitPageflip(_this, windata)) {
	SDL_LogError(SDL_LOG_CATEGORY_VIDEO, "Immediate wait for previous pageflip failed");
	return 0;
	}
	}

	return 1;
	}

	SDL_EGL_MakeCurrent_impl(KMSDRM)

	#endif /* SDL_VIDEO_DRIVER_KMSDRM */

	/* vi: set ts=4 sw=4 expandtab: */