Differential D4455 Diff 14275 source/blender/draw/modes/shaders/object_grid_frag.glsl

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source/blender/draw/modes/shaders/object_grid_frag.glsl

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	#define M_1_SQRTPI 0.5641895835477563 /* 1/sqrt(pi) */			#define M_1_SQRTPI 0.5641895835477563 /* 1/sqrt(pi) */

	/**			/**
	* We want to know how much a pixel is covered by a line.			* We want to know how much a pixel is covered by a line.
	* We replace the square pixel with acircle of the same area and try to find the intersection area.			* We replace the square pixel with acircle of the same area and try to find the intersection area.
	* The area we search is the circular segment. https://en.wikipedia.org/wiki/Circular_segment			* The area we search is the circular segment. https://en.wikipedia.org/wiki/Circular_segment
	* The formula for the area uses inverse trig function and is quite complexe.			* The formula for the area uses inverse trig function and is quite complexe.
	* Instead, we approximate it by using the smoothstep function and a 1.05 factor to the disc radius.			* Instead, we approximate it by using the smoothstep function and a 1.05 factor to the disc radius.
	**/			*/
	#define DISC_RADIUS (M_1_SQRTPI * 1.05)			#define DISC_RADIUS (M_1_SQRTPI * 1.05)
	#define GRID_LINE_SMOOTH_START (0.5 - DISC_RADIUS)			#define GRID_LINE_SMOOTH_START (0.5 - DISC_RADIUS)
	#define GRID_LINE_SMOOTH_END (0.5 + DISC_RADIUS)			#define GRID_LINE_SMOOTH_END (0.5 + DISC_RADIUS)

	float get_grid(vec2 co, vec2 fwidthCos, float grid_size)			float get_grid(vec2 co, vec2 fwidthCos, float grid_size)
	{			{
	float half_size = grid_size / 2.0;			float half_size = grid_size / 2.0;
	/* triangular wave pattern, amplitude is [0, half_size] */			/* triangular wave pattern, amplitude is [0, half_size] */
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