/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2015 by Blender Foundation
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): Dalai Felinto
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/** \file blender/windowmanager/intern/wm_stereo.c
 *  \ingroup wm
 */


#include <stdlib.h>
#include <string.h>

#include "DNA_listBase.h"

#include "RNA_access.h"

#include "MEM_guardedalloc.h"

#include "BLI_listbase.h"
#include "BLI_utildefines.h"

#include "BIF_gl.h"

#include "BKE_context.h"
#include "BKE_global.h"
#include "BKE_report.h"

#include "GHOST_C-api.h"

#include "ED_screen.h"

#include "GPU_immediate.h"
#include "GPU_framebuffer.h"
#include "GPU_texture.h"

#include "WM_api.h"
#include "WM_types.h"
#include "wm.h"
#include "wm_draw.h"
#include "wm_window.h"

#include "UI_interface.h"
#include "UI_resources.h"

static GPUInterlaceShader interlace_gpu_id_from_type(eStereo3dInterlaceType interlace_type)
{
	switch (interlace_type) {
		case S3D_INTERLACE_ROW:
			return GPU_SHADER_INTERLACE_ROW;
		case S3D_INTERLACE_COLUMN:
			return GPU_SHADER_INTERLACE_COLUMN;
		case S3D_INTERLACE_CHECKERBOARD:
		default:
			return GPU_SHADER_INTERLACE_CHECKER;
	}
}

void wm_stereo3d_draw_interlace(wmWindow *win, ARegion *ar)
{
	bool swap = (win->stereo3d_format->flag & S3D_INTERLACE_SWAP) != 0;
	enum eStereo3dInterlaceType interlace_type = win->stereo3d_format->interlace_type;

	/* wmOrtho for the screen has this same offset */
	float halfx = GLA_PIXEL_OFS / ar->winx;
	float halfy = GLA_PIXEL_OFS / ar->winy;

	GPUVertFormat *format = immVertexFormat();
	uint texcoord = GPU_vertformat_attr_add(format, "texCoord", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
	uint pos = GPU_vertformat_attr_add(format, "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);

	/* leave GL_TEXTURE0 as the latest active texture */
	for (int view = 1; view >= 0; view--) {
		GPUTexture *texture = wm_draw_region_texture(ar, view);
		glActiveTexture(GL_TEXTURE0 + view);
		glBindTexture(GL_TEXTURE_2D, GPU_texture_opengl_bindcode(texture));
	}

	immBindBuiltinProgram(GPU_SHADER_2D_IMAGE_INTERLACE);
	immUniform1i("image_a", (swap) ? 1 : 0);
	immUniform1i("image_b", (swap) ? 0 : 1);

	immUniform1i("interlace_id", interlace_gpu_id_from_type(interlace_type));

	immBegin(GPU_PRIM_TRI_FAN, 4);

	immAttrib2f(texcoord, halfx, halfy);
	immVertex2f(pos, ar->winrct.xmin, ar->winrct.ymin);

	immAttrib2f(texcoord, 1.0f + halfx, halfy);
	immVertex2f(pos, ar->winrct.xmax + 1, ar->winrct.ymin);

	immAttrib2f(texcoord, 1.0f + halfx, 1.0f + halfy);
	immVertex2f(pos, ar->winrct.xmax + 1, ar->winrct.ymax + 1);

	immAttrib2f(texcoord, halfx, 1.0f + halfy);
	immVertex2f(pos, ar->winrct.xmin, ar->winrct.ymax + 1);

	immEnd();
	immUnbindProgram();

	for (int view = 1; view >= 0; view--) {
		glActiveTexture(GL_TEXTURE0 + view);
		glBindTexture(GL_TEXTURE_2D, 0);
	}
}

void wm_stereo3d_draw_anaglyph(wmWindow *win, ARegion *ar)
{
	for (int view = 0; view < 2; view ++) {
		int bit = view + 1;

		switch (win->stereo3d_format->anaglyph_type) {
			case S3D_ANAGLYPH_REDCYAN:
				glColorMask((1&bit) ? GL_TRUE : GL_FALSE,
				            (2&bit) ? GL_TRUE : GL_FALSE,
				            (2&bit) ? GL_TRUE : GL_FALSE,
				            GL_FALSE);
				break;
			case S3D_ANAGLYPH_GREENMAGENTA:
				glColorMask((2&bit) ? GL_TRUE : GL_FALSE,
				            (1&bit) ? GL_TRUE : GL_FALSE,
				            (2&bit) ? GL_TRUE : GL_FALSE,
				            GL_FALSE);
				break;
			case S3D_ANAGLYPH_YELLOWBLUE:
				glColorMask((1&bit) ? GL_TRUE : GL_FALSE,
				            (1&bit) ? GL_TRUE : GL_FALSE,
				            (2&bit) ? GL_TRUE : GL_FALSE,
				            GL_FALSE);
				break;
		}

		wm_draw_region_blend(ar, view, false);
	}

	glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
}

void wm_stereo3d_draw_sidebyside(wmWindow *win, int view)
{
	bool cross_eyed = (win->stereo3d_format->flag & S3D_SIDEBYSIDE_CROSSEYED) != 0;

	GPUVertFormat *format = immVertexFormat();
	uint texcoord = GPU_vertformat_attr_add(format, "texCoord", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
	uint pos = GPU_vertformat_attr_add(format, "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);

	immBindBuiltinProgram(GPU_SHADER_2D_IMAGE);

	int soffx = WM_window_pixels_x(win) * 0.5f;
	if (view == STEREO_LEFT_ID) {
		if (!cross_eyed)
			soffx = 0;
	}
	else { //RIGHT_LEFT_ID
		if (cross_eyed)
			soffx = 0;
	}

	const int sizex = WM_window_pixels_x(win);
	const int sizey = WM_window_pixels_y(win);

	/* wmOrtho for the screen has this same offset */
	const float halfx = GLA_PIXEL_OFS / sizex;
	const float halfy = GLA_PIXEL_OFS / sizex;

	immUniform1i("image", 0); /* texture is already bound to GL_TEXTURE0 unit */

	immBegin(GPU_PRIM_TRI_FAN, 4);

	immAttrib2f(texcoord, halfx, halfy);
	immVertex2f(pos, soffx, 0.0f);

	immAttrib2f(texcoord, 1.0f + halfx, halfy);
	immVertex2f(pos, soffx + (sizex * 0.5f), 0.0f);

	immAttrib2f(texcoord, 1.0f + halfx, 1.0f + halfy);
	immVertex2f(pos, soffx + (sizex * 0.5f), sizey);

	immAttrib2f(texcoord, halfx, 1.0f + halfy);
	immVertex2f(pos, soffx, sizey);

	immEnd();

	immUnbindProgram();
}

void wm_stereo3d_draw_topbottom(wmWindow *win, int view)
{
	GPUVertFormat *format = immVertexFormat();
	uint texcoord = GPU_vertformat_attr_add(format, "texCoord", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
	uint pos = GPU_vertformat_attr_add(format, "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);

	immBindBuiltinProgram(GPU_SHADER_2D_IMAGE);

	int soffy;
	if (view == STEREO_LEFT_ID) {
		soffy = WM_window_pixels_y(win) * 0.5f;
	}
	else { /* STEREO_RIGHT_ID */
		soffy = 0;
	}

	const int sizex = WM_window_pixels_x(win);
	const int sizey = WM_window_pixels_y(win);

	/* wmOrtho for the screen has this same offset */
	const float halfx = GLA_PIXEL_OFS / sizex;
	const float halfy = GLA_PIXEL_OFS / sizex;

	immUniform1i("image", 0); /* texture is already bound to GL_TEXTURE0 unit */

	immBegin(GPU_PRIM_TRI_FAN, 4);

	immAttrib2f(texcoord, halfx, halfy);
	immVertex2f(pos, 0.0f, soffy);

	immAttrib2f(texcoord, 1.0f + halfx, halfy);
	immVertex2f(pos, sizex, soffy);

	immAttrib2f(texcoord, 1.0f + halfx, 1.0f + halfy);
	immVertex2f(pos, sizex, soffy + (sizey * 0.5f));

	immAttrib2f(texcoord, halfx, 1.0f + halfy);
	immVertex2f(pos, 0.0f, soffy + (sizey * 0.5f));

	immEnd();

	immUnbindProgram();
}


static bool wm_stereo3d_quadbuffer_supported(void)
{
	GLboolean stereo = GL_FALSE;
	glGetBooleanv(GL_STEREO, &stereo);
	return stereo == GL_TRUE;
}

static bool wm_stereo3d_is_fullscreen_required(eStereoDisplayMode stereo_display)
{
	return ELEM(stereo_display,
	            S3D_DISPLAY_SIDEBYSIDE,
	            S3D_DISPLAY_TOPBOTTOM);
}

bool WM_stereo3d_enabled(wmWindow *win, bool skip_stereo3d_check)
{
	const bScreen *screen = WM_window_get_active_screen(win);
	const Scene *scene = WM_window_get_active_scene(win);

	/* some 3d methods change the window arrangement, thus they shouldn't
	 * toggle on/off just because there is no 3d elements being drawn */
	if (wm_stereo3d_is_fullscreen_required(win->stereo3d_format->display_mode)) {
		return GHOST_GetWindowState(win->ghostwin) == GHOST_kWindowStateFullScreen;
	}

	if ((skip_stereo3d_check == false) && (ED_screen_stereo3d_required(screen, scene) == false)) {
		return false;
	}

	/* some 3d methods change the window arrangement, thus they shouldn't
	 * toggle on/off just because there is no 3d elements being drawn */
	if (wm_stereo3d_is_fullscreen_required(win->stereo3d_format->display_mode)) {
		return GHOST_GetWindowState(win->ghostwin) == GHOST_kWindowStateFullScreen;
	}

	return true;
}

/**
 * If needed, this adjusts \a r_mouse_xy so that drawn cursor and handled mouse position are matching visually.
 */
void wm_stereo3d_mouse_offset_apply(wmWindow *win, int *r_mouse_xy)
{
	if (!WM_stereo3d_enabled(win, false))
		return;

	if (win->stereo3d_format->display_mode == S3D_DISPLAY_SIDEBYSIDE) {
		const int half_x = win->sizex / 2;
		/* right half of the screen */
		if (r_mouse_xy[0] > half_x) {
			r_mouse_xy[0] -= half_x;
		}
		r_mouse_xy[0] *= 2;
	}
	else if (win->stereo3d_format->display_mode == S3D_DISPLAY_TOPBOTTOM) {
		const int half_y = win->sizey / 2;
		/* upper half of the screen */
		if (r_mouse_xy[1] > half_y) {
			r_mouse_xy[1] -= half_y;
		}
		r_mouse_xy[1] *= 2;
	}
}

/************************** Stereo 3D operator **********************************/
typedef struct Stereo3dData {
	Stereo3dFormat stereo3d_format;
} Stereo3dData;

static bool wm_stereo3d_set_properties(bContext *UNUSED(C), wmOperator *op)
{
	Stereo3dData *s3dd = op->customdata;
	Stereo3dFormat *s3d = &s3dd->stereo3d_format;
	PropertyRNA *prop;
	bool is_set = false;

	prop = RNA_struct_find_property(op->ptr, "display_mode");
	if (RNA_property_is_set(op->ptr, prop)) {
		s3d->display_mode = RNA_property_enum_get(op->ptr, prop);
		is_set = true;
	}

	prop = RNA_struct_find_property(op->ptr, "anaglyph_type");
	if (RNA_property_is_set(op->ptr, prop)) {
		s3d->anaglyph_type = RNA_property_enum_get(op->ptr, prop);
		is_set = true;
	}

	prop = RNA_struct_find_property(op->ptr, "interlace_type");
	if (RNA_property_is_set(op->ptr, prop)) {
		s3d->interlace_type = RNA_property_enum_get(op->ptr, prop);
		is_set = true;
	}

	prop = RNA_struct_find_property(op->ptr, "use_interlace_swap");
	if (RNA_property_is_set(op->ptr, prop)) {
		if (RNA_property_boolean_get(op->ptr, prop))
			s3d->flag |= S3D_INTERLACE_SWAP;
		else
			s3d->flag &= ~S3D_INTERLACE_SWAP;
		is_set = true;
	}

	prop = RNA_struct_find_property(op->ptr, "use_sidebyside_crosseyed");
	if (RNA_property_is_set(op->ptr, prop)) {
		if (RNA_property_boolean_get(op->ptr, prop))
			s3d->flag |= S3D_SIDEBYSIDE_CROSSEYED;
		else
			s3d->flag &= ~S3D_SIDEBYSIDE_CROSSEYED;
		is_set = true;
	}

	return is_set;
}

static void wm_stereo3d_set_init(bContext *C, wmOperator *op)
{
	Stereo3dData *s3dd;
	wmWindow *win = CTX_wm_window(C);

	op->customdata = s3dd = MEM_callocN(sizeof(Stereo3dData), __func__);

	/* store the original win stereo 3d settings in case of cancel */
	s3dd->stereo3d_format = *win->stereo3d_format;
}

int wm_stereo3d_set_exec(bContext *C, wmOperator *op)
{
	wmWindowManager *wm = CTX_wm_manager(C);
	wmWindow *win_src = CTX_wm_window(C);
	wmWindow *win_dst = NULL;
	const bool is_fullscreen = WM_window_is_fullscreen(win_src);
	char prev_display_mode = win_src->stereo3d_format->display_mode;
	Stereo3dData *s3dd;
	bool ok = true;

	if (G.background)
		return OPERATOR_CANCELLED;

	if (op->customdata == NULL) {
		/* no invoke means we need to set the operator properties here */
		wm_stereo3d_set_init(C, op);
		wm_stereo3d_set_properties(C, op);
	}

	s3dd = op->customdata;
	*win_src->stereo3d_format = s3dd->stereo3d_format;

	if (prev_display_mode == S3D_DISPLAY_PAGEFLIP &&
	    prev_display_mode != win_src->stereo3d_format->display_mode)
	{
		/* in case the hardware supports pageflip but not the display */
		if ((win_dst = wm_window_copy_test(C, win_src, false, false))) {
			/* pass */
		}
		else {
			BKE_report(op->reports, RPT_ERROR,
			           "Failed to create a window without quad-buffer support, you may experience flickering");
			ok = false;
		}
	}
	else if (win_src->stereo3d_format->display_mode == S3D_DISPLAY_PAGEFLIP) {
		const bScreen *screen = WM_window_get_active_screen(win_src);

		/* ED_workspace_layout_duplicate() can't handle other cases yet T44688 */
		if (screen->state != SCREENNORMAL) {
			BKE_report(op->reports, RPT_ERROR,
			           "Failed to switch to Time Sequential mode when in fullscreen");
			ok = false;
		}
		/* pageflip requires a new window to be created with the proper OS flags */
		else if ((win_dst = wm_window_copy_test(C, win_src, false, false))) {
			if (wm_stereo3d_quadbuffer_supported()) {
				BKE_report(op->reports, RPT_INFO, "Quad-buffer window successfully created");
			}
			else {
				wm_window_close(C, wm, win_dst);
				win_dst = NULL;
				BKE_report(op->reports, RPT_ERROR, "Quad-buffer not supported by the system");
				ok = false;
			}
		}
		else {
			BKE_report(op->reports, RPT_ERROR,
			           "Failed to create a window compatible with the time sequential display method");
			ok = false;
		}
	}

	if (wm_stereo3d_is_fullscreen_required(s3dd->stereo3d_format.display_mode)) {
		if (!is_fullscreen) {
			BKE_report(op->reports, RPT_INFO, "Stereo 3D Mode requires the window to be fullscreen");
		}
	}

	MEM_freeN(op->customdata);

	if (ok) {
		if (win_dst) {
			wm_window_close(C, wm, win_src);
		}

		WM_event_add_notifier(C, NC_WINDOW, NULL);
		return OPERATOR_FINISHED;
	}
	else {
		/* without this, the popup won't be freed freed properly T44688 */
		CTX_wm_window_set(C, win_src);
		win_src->stereo3d_format->display_mode = prev_display_mode;
		return OPERATOR_CANCELLED;
	}
}

int wm_stereo3d_set_invoke(bContext *C, wmOperator *op, const wmEvent *UNUSED(event))
{
	wm_stereo3d_set_init(C, op);

	if (wm_stereo3d_set_properties(C, op))
		return wm_stereo3d_set_exec(C, op);
	else
		return WM_operator_props_dialog_popup(C, op, 250, 100);
}

void wm_stereo3d_set_draw(bContext *UNUSED(C), wmOperator *op)
{
	Stereo3dData *s3dd = op->customdata;
	PointerRNA stereo3d_format_ptr;
	uiLayout *layout = op->layout;
	uiLayout *col;

	RNA_pointer_create(NULL, &RNA_Stereo3dDisplay, &s3dd->stereo3d_format, &stereo3d_format_ptr);

	col = uiLayoutColumn(layout, false);
	uiItemR(col, &stereo3d_format_ptr, "display_mode", 0, NULL, ICON_NONE);

	switch (s3dd->stereo3d_format.display_mode) {
		case S3D_DISPLAY_ANAGLYPH:
		{
			uiItemR(col, &stereo3d_format_ptr, "anaglyph_type", 0, NULL, ICON_NONE);
			break;
		}
		case S3D_DISPLAY_INTERLACE:
		{
			uiItemR(col, &stereo3d_format_ptr, "interlace_type", 0, NULL, ICON_NONE);
			uiItemR(col, &stereo3d_format_ptr, "use_interlace_swap", 0, NULL, ICON_NONE);
			break;
		}
		case S3D_DISPLAY_SIDEBYSIDE:
		{
			uiItemR(col, &stereo3d_format_ptr, "use_sidebyside_crosseyed", 0, NULL, ICON_NONE);
			/* fall-through */
		}
		case S3D_DISPLAY_PAGEFLIP:
		case S3D_DISPLAY_TOPBOTTOM:
		default:
		{
			break;
		}
	}
}

bool wm_stereo3d_set_check(bContext *UNUSED(C), wmOperator *UNUSED(op))
{
	/* the check function guarantees that the menu is updated to show the
	 * sub-options when an enum change (e.g., it shows the anaglyph options
	 * when anaglyph is on, and the interlace options when this is on */
	return true;
}

void wm_stereo3d_set_cancel(bContext *UNUSED(C), wmOperator *op)
{
	MEM_freeN(op->customdata);
	op->customdata = NULL;
}