slang-shaders/bezel/Mega_Bezel/shaders/HyperspaceMadness/hsm/common/hsm-common-functions-bezel.inc

/*
    Mega Bezel - Creates a graphic treatment for the game play area to give a retro feel
    Copyright (C) 2019-2021 HyperspaceMadness - HyperspaceMadness@outlook.com

    Incorporates much great feedback from the libretro forum, and thanks 
    to Hunterk who helped me get started

    See more at the libretro forum
    https://forums.libretro.com/t/hsm-mega-bezel-reflection-shader-feedback-and-updates

    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 3 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, see <https://www.gnu.org/licenses/>.
*/

vec2 HSM_GetOuterBezelScale(vec2 screen_scale, float screen_aspect)
{
	vec2 bezel_outer_scale_offset = vec2(HSM_BZL_WIDTH / screen_aspect + 1, HSM_BZL_HEIGHT + 1);
	return bezel_outer_scale_offset;
}

vec2 GetDefaultScreenScale()
{
	float output_aspect = global.FinalViewportSize.x / global.FinalViewportSize.y;
	vec2 out_placement_scale = DEFAULT_UNCORRECTED_SCREEN_SCALE;
	out_placement_scale.x /= output_aspect;
	return out_placement_scale;
}

vec2 GetDefaultBezelScale()
{
	float output_aspect = global.FinalViewportSize.x / global.FinalViewportSize.y;
	vec2 out_placement_scale = DEFAULT_UNCORRECTED_BEZEL_SCALE;
	out_placement_scale.x /= output_aspect;
	return out_placement_scale;
}

float HSM_GetBezelCoords(vec2 screen_coord, 
							vec2 screen_scale, 
							vec2 tube_scale, 
							float screen_aspect, 
							bool curve_coords_on,
							inout vec2 bezel_outside_scale,
							inout vec2 bezel_outside_coord, 
							inout vec2 bezel_outside_curved_coord, 
							inout vec2 frame_outside_coord)
{
	float output_aspect = global.OutputSize.x / global.OutputSize.y;

	vec2 bezel_outer_pos_offset = vec2(0, HSM_BZL_OUTER_POSITION_Y);
	vec2 bezel_outer_scale_offset = HSM_GetOuterBezelScale(screen_scale, screen_aspect);

	bezel_outside_coord = screen_coord + bezel_outer_pos_offset;
	bezel_outside_curved_coord = bezel_outside_coord;

	// Only run curved coordinates if requested or we are using tilt
	if (curve_coords_on)
		if ((HSM_CURVATURE_MODE > 0) && ((HSM_CURVATURE_3D_TILT_ANGLE_X != 0) || (HSM_CURVATURE_3D_TILT_ANGLE_Y != 0)))
			bezel_outside_curved_coord = HSM_GetCurvedCoord(bezel_outside_curved_coord, 0, bezel_outer_scale_offset.x * output_aspect / bezel_outer_scale_offset.y);

	vec2 black_edge_scale_offset = tube_scale / screen_scale;

	bezel_outside_scale.xy = screen_scale * black_edge_scale_offset * bezel_outer_scale_offset;
	// bezel_outside_transform.zw = -vec2(HSM_SCREEN_POSITION_X, HSM_SCREEN_POSITION_Y) + bezel_outer_pos_offset * screen_scale;

	bezel_outside_coord = HSM_GetInverseScaledCoord(bezel_outside_curved_coord, black_edge_scale_offset * bezel_outer_scale_offset) + vec2(0, HSM_BZL_OUTER_POSITION_Y);
	bezel_outside_curved_coord = HSM_GetInverseScaledCoord(bezel_outside_curved_coord, black_edge_scale_offset * bezel_outer_scale_offset) + vec2(0, HSM_BZL_OUTER_POSITION_Y);

	frame_outside_coord = (bezel_outside_curved_coord + 
							vec2(0, HSM_FRM_OUTER_POS_Y) - 0.5) / 
							vec2((HSM_FRM_THICKNESS * HSM_FRM_THICKNESS_SCALE_X) / 
							(screen_scale.x / screen_scale.y * output_aspect) + 1, 
							HSM_FRM_THICKNESS + 1) + 0.5;

	if (HSM_BZL_OUTER_CURVATURE_SCALE > 0)
	{
		if (curve_coords_on)
			bezel_outside_curved_coord = HSM_GetTubeCurvedCoord(bezel_outside_curved_coord, HSM_BZL_OUTER_CURVATURE_SCALE, screen_scale, tube_scale, bezel_outer_scale_offset.x * global.OutputSize.x / global.OutputSize.y / bezel_outer_scale_offset.y, 0);

		if (curve_coords_on)
			if ( HSM_FRM_OUTER_CURVATURE_SCALE > 0)
				frame_outside_coord = HSM_GetTubeCurvedCoord(frame_outside_coord, HSM_BZL_OUTER_CURVATURE_SCALE * HSM_FRM_OUTER_CURVATURE_SCALE, screen_scale, tube_scale, bezel_outer_scale_offset.x * global.OutputSize.x / global.OutputSize.y / bezel_outer_scale_offset.y, 0);
	}
	
	DEFAULT_SCREEN_SCALE = GetDefaultScreenScale();
	DEFAULT_BEZEL_SCALE = GetDefaultBezelScale();

	return 0;
}

// Change Transforms for Scale

// Applies the position before scaling from the center
// Should allow having an image where the center of the tube in the graphic is off center
// the position offset moves it so the screen is centered, then the graphic is scaled from the center 
vec2 HSM_AddPosScaleToCoord(vec2 in_base_coord, vec2 in_base_scale, vec2 in_pos, vec2 in_scale)
{
	// out_coord += in_base_scale * in_transform.zw;
	vec2 positioned_coord = in_base_coord + in_pos;
	vec2 out_coord = HSM_GetInverseScaledCoord(positioned_coord, in_scale);
	return out_coord;
}

float MAX_LAYER_ORDER = 12;

bool HSM_GetUseTubeStaticReflection()
{
	return HSM_TUBE_STATIC_REFLECTION_IMAGE_ON > 0.5 && HSM_GetUseOnCurrentScreenIndex(HSM_TUBE_STATIC_REFLECTION_IMAGE_DUALSCREEN_VIS_MODE);
}

bool HSM_GetUseTubeDiffuseImage()
{
	return HSM_TUBE_DIFFUSE_MODE == 1 && HSM_GetUseOnCurrentScreenIndex(HSM_TUBE_DIFFUSE_IMAGE_DUALSCREEN_VIS_MODE);
}

bool HSM_GetUseTubeColoredGelImage()
{
	return HSM_TUBE_COLORED_GEL_IMAGE_ON > 0.5 && HSM_GetUseOnCurrentScreenIndex(HSM_TUBE_COLORED_GEL_IMAGE_DUALSCREEN_VIS_MODE);
}

vec4 HSM_GetTubeHighlight(vec2 tube_curved_coord, bool apply_to_mirror, in sampler2D TubeStaticReflectionImage, vec4 ambient_lighting_image)
{
	tube_curved_coord = HSM_GetViewportCoordWithFlip(tube_curved_coord);
	vec4 out_color = vec4(0);

	vec2 mirrored_tube_coord = tube_curved_coord;
	if (apply_to_mirror)
		mirrored_tube_coord = HSM_GetMirrorWrappedCoord(tube_curved_coord);

	float bezel_corner_radius = HSM_BZL_INNER_CORNER_RADIUS_SCALE * HSM_GLOBAL_CORNER_RADIUS;
	if(HSM_BZL_USE_INDEPENDENT_CURVATURE > 0)
		bezel_corner_radius = HSM_BZL_INNER_CORNER_RADIUS_SCALE * DEFAULT_SCREEN_CORNER_RADIUS;

	vec2 tube_highlight_coord = (mirrored_tube_coord - 0.5) / HSM_TUBE_STATIC_REFLECTION_IMAGE_SCALE + 0.5;

	tube_highlight_coord.x = (tube_highlight_coord.x - 0.5) * HSM_FLIP_VIEWPORT_HORIZONTAL + 0.5;
	tube_highlight_coord.y = (tube_highlight_coord.y - 0.5) * HSM_FLIP_VIEWPORT_VERTICAL + 0.5;
/*
	// Dithering for the glass reflection if needed to reduce banding
	float blur_max_size = 1;
	float blur_amount = 0.2;
	vec4 tube_highlight_image = HSM_GetStoichaicBlurredSample(TubeStaticReflectionImage, tube_highlight_coord, HSM_TUBE_STATIC_REFLECTION_IMAGE_DITHERING_SAMPLES, blur_max_size, blur_amount);
*/
	// Mask the very outer edge of the tube for a very small shadowing effect
	float tube_highlight_mask = HSM_GetCornerMask((tube_curved_coord - 0.5) + 0.5 , SCREEN_ASPECT, HSM_BZL_INNER_CORNER_RADIUS_SCALE * HSM_GLOBAL_CORNER_RADIUS, 0.9);

	vec4 tube_highlight_image = HSM_GetMipmappedTexSample(TubeStaticReflectionImage, tube_highlight_coord, TUBE_SCALE, 0);

	tube_highlight_image = HSM_Linearize(tube_highlight_image, DEFAULT_SRGB_GAMMA) * tube_highlight_mask;

	if (HSM_TUBE_STATIC_REFLECTION_IMAGE_AMBIENT_LIGHTING > 0)
	{
		ambient_lighting_image.rgb = (1 - HSM_TUBE_STATIC_REFLECTION_IMAGE_AMBIENT_LIGHTING) * vec3(1) + HSM_TUBE_STATIC_REFLECTION_IMAGE_AMBIENT_LIGHTING * ambient_lighting_image.rgb;
		tube_highlight_image.rgb *= ambient_lighting_image.rgb;
	}

	out_color = HSM_TUBE_STATIC_REFLECTION_IMAGE_OPACITY * tube_highlight_image * tube_highlight_image.a;
	out_color.rgb *= HSM_GLOBAL_GRAPHICS_BRIGHTNESS;

	return out_color;
}