Shader Debugger

Godot Shader Debugger

Allows for basic data debugging from native gdscript code.

Works with Canvas, Spatial, and Sky shaders.

Displays values for floats, vectors and matricies. Values limited to -99.999 to 99.999. Float values are a little rough, use the Fix Floats toggle for integers. Obviously only works for per-frame rendered values, not per-pixel. Edit position and size in shader uniform controls in editor. Easy to add to existing code.

Adapted from villain749 on reddit:  

https://www.reddit.com/r/GraphicsProgramming/comments/12m1d36/comment/jg939n4  

To Use:

  • Copy the code in to your script  

Debug dbg = debug_construct(UV);

  • Construct a dbg struct, passing a UV
  • Use SCREEN_UV for sky (ONLY WORKS in forward_plus rendering)  

void my_func( inout Debug dbg ) {}

  • Pass the dbg to any function

dbgFloat(dbg, value);

  • Call the function for your value

debug_finish(color, dbg);

  • Pass your color to the finisher before applying
Shader code
shader_type canvas_item;


// Copy code from here to bottom


group_uniforms Debug;
// Click here to hide code

	uniform float dbg_text_scale : hint_range(0.2, 20.0, 0.2) = 4.0;
	uniform float dbg_text_offset : hint_range(0.0, 0.5, 0.02) = 0.08;
	uniform float dbg_alpha : hint_range(0.0, 1.0, 0.1) = 0.2;
	uniform float dbg_size_x : hint_range(0.0, 1.0, 0.05) = 0.9;
	uniform float dbg_size_y : hint_range(0.0, 1.0, 0.05) = 0.9;
	uniform float dbg_pos_x : hint_range(0.0, 1.0, 0.05) = 0.5;
	uniform float dbg_pos_y : hint_range(0.0, 1.0, 0.05) = 0.5;
	uniform bool dbg_fix_floats = true;
	struct Debug {
		vec2 uv;
		vec2 pos;
		float result;
		float scale;
		float addY;
		bool onUV;
	};
	
	const vec2 digit_divs = vec2(4.0, 5.0);
	const int digit_mask[10] = int[10](480599, 139810, 476951, 476999, 350020, 464711, 464727, 476228, 481111, 481095);
	const int cell_mask[20] = int[20](1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 131072, 262144, 524288);
	const int min_mask = 1792;
	const int dot_mask = 2;
	const int remap_digits[7] = int[7](0,0,1,0,2,3,4);
	int getDigit(float fnum, int place) {
		float num = clamp(abs(fnum), 0.0001, 99.999);
		float sm_num = num / 100.0; // 3 decimal places
		int number = int(fract(sm_num * pow(10.0, float(place))) * 10.0);
		return clamp(number, 0, 9);
	}
	void runFloat(inout Debug dbg, in float number, in vec2 addPos) {
		float num_val = number;
		if (dbg_fix_floats) { num_val += num_val < 0.0 ? -0.001 : 0.001; }
		vec2 pos_uv = vec2(dbg.pos.x,1.0-dbg.pos.y) + vec2(addPos.x,-addPos.y);
		vec2 uv_base = vec2(dbg.uv.x,1.0-dbg.uv.y);
		float size = dbg.scale / 100.0;
		vec2 uv_sc = (uv_base - pos_uv) * vec2(1.0 / (size * 5.0), 1.0 / size) + pos_uv + vec2(0.142,1.0);	
		float box_stencil = 1.0;
		float bsx = uv_sc.x > 1.0 + pos_uv.x ? 0.0 :box_stencil;
		box_stencil = uv_sc.x < 0.0 + pos_uv.x ? 0.0 : bsx;
		float bsy = uv_sc.y > 1.0 + pos_uv.y ? 0.0 : box_stencil;
		box_stencil = uv_sc.y < 0.0 + pos_uv.y ? 0.0 : bsy;
		vec2 digit_split = clamp((uv_sc - pos_uv) * vec2(7.0,1.0), vec2(0.0, 0.0), vec2(7.0, 1.0));
		int digit_id = int(floor(digit_split.x));
		vec2 digit_uv = fract(digit_split);
		ivec2 uv_cells = ivec2(floor(digit_uv * digit_divs));
		int cell_id = clamp(int(uv_cells.y * int(digit_divs.x) + uv_cells.x), 0, 19);
		float result = 0.0;
		if (digit_id == 0 && num_val < 0.0) {
			result = float(cell_mask[cell_id] & min_mask);
		}
		else if (digit_id == 3) {
			result = float(cell_mask[cell_id] & dot_mask);
		}
		else if (digit_id != 0 && digit_id != 3){
			int digit = getDigit(num_val, remap_digits[digit_id]);
			result = float(cell_mask[cell_id] & digit_mask[digit]);
		}
		dbg.result += result * box_stencil;
	}
	
	void dbgFloat(inout Debug dbg, in float number) {
		if (dbg.onUV) {
			runFloat( dbg, number, vec2(0.0));
			dbg.pos.y += dbg.addY;
		}
	}
	void dbgVec2(inout Debug dbg, vec2 vector) {
		if (dbg.onUV) {
			float space = dbg.scale * 0.06;
			runFloat(dbg, vector.x, vec2(0.0));
			runFloat(dbg, vector.y, vec2(space,0.0));
			dbg.pos.y += dbg.addY;
		}
	}
	void dbgVec3(inout Debug dbg, vec3 vector) {
		if (dbg.onUV) {
			float space = dbg.scale * 0.06;
			runFloat(dbg, vector.x, vec2(0.0));
			runFloat(dbg, vector.y, vec2(space,0.0));
			runFloat(dbg, vector.z, vec2(space+space,0.0));
			dbg.pos.y += dbg.addY;
		}
	}
	void dbgVec4(inout Debug dbg, vec4 vector) {
		if (dbg.onUV) {
			float space = dbg.scale * 0.06;
			runFloat(dbg, vector.x, vec2(0.0));
			runFloat(dbg, vector.y, vec2(space,0.0));
			runFloat(dbg, vector.z, vec2(space+space,0.0));
			runFloat(dbg, vector.w, vec2(space+space+space,0.0));
			dbg.pos.y += dbg.addY;
		}
	}
	void dbgMat3(inout Debug dbg, in mat3 mat) {
		if (dbg.onUV) {
			vec3 m1 = mat[0];
			vec3 m2 = mat[1];
			vec3 m3 = mat[2];
			dbgVec3(dbg, m1);
			dbgVec3(dbg, m2);
			dbgVec3(dbg, m3);
		}
	}
	void dbgMat4(inout Debug dbg, in mat4 mat) {
		if (dbg.onUV) {
			vec4 m1 = mat[0];
			vec4 m2 = mat[1];
			vec4 m3 = mat[2];
			vec4 m4 = mat[2];
			dbgVec4(dbg, m1);
			dbgVec4(dbg, m2);
			dbgVec4(dbg, m3);
			dbgVec4(dbg, m4);
		}
	}
	void dbgSpacer(inout Debug dbg) {
		dbg.pos.y += dbg.addY;
	}



	void debug_finish( inout vec3 set, inout Debug dbg ) {
		if (dbg.onUV) {
			vec3 col = vec3(0.01);
			col.r = dbg.result;
			float m = dbg_alpha;
			m = -pow(2.0, -10.0 * dbg_alpha) + 1.0;
			set = mix(set,col,m);
		}
	}
	Debug debug_construct( in vec2 screen_uv ) {
		Debug dbg;
		dbg.uv = screen_uv;
		dbg.uv.x -= (1.0-dbg_size_x)*dbg_pos_x;
		dbg.uv.y -= (1.0-dbg_size_y)*dbg_pos_y;
		dbg.uv /= vec2(dbg_size_x,dbg_size_y);
		dbg.pos = vec2(dbg_text_offset);
		dbg.result = 0.0;
		dbg.scale = dbg_text_scale;
		dbg.addY = dbg_text_scale / 80.0;
		dbg.onUV = false;
		if (dbg.uv.x > 0.0 && dbg.uv.x < 1.0 && dbg.uv.y > 0.0 && dbg.uv.y < 1.0) {
			dbg.onUV = true;
		}
		return dbg;
	}
	
	/**
		* // Functions:
		* debug_construct
		* debug_finish
		* 
		* dbgFloat
		* dbgVec2
		* dbgVec3
		* dbgVec4
		* dbgMat3
		* dbgMat4
		* 
		* dbgSpacer
		* //
		* 
		* 
		* Godot Shader Debugger
		* Adapted from villain749 on reddit:
		* https://www.reddit.com/r/GraphicsProgramming/comments/12m1d36/comment/jg939n4
		* 
		* Displays values for floats, vectors and matricies
		* Values limited to -99.999 to 99.999
		* Float values are a little rough, use the Fix Floats toggle for integers
		* Obviously only works for per-frame rendered values
		* Easy to add to existing code
		* 
		* 	To Use:
		* Debug dbg = debug_construct(UV);
		*		// Construct a dbg, passing a UV
		*		// Use SCREEN_UV for sky (ONLY WORKS in forward_plus rendering)
		* void my_func( inout Debug dbg ) {}
		*		// Pass the dbg to any function
		* dbgFloat(dbg, value);
		*		// Call the function for your value
		*		// See above for all available value functions
		* debug_finish(color, dbg);
		*		// Pass your color to the finisher before applying
	*/
	
	//  Debug code can be folded (hidden) at top


// Copy code from here to top





void draw_canvas( inout vec3 set, in vec2 uv, in float s, in float c ) {
	float v = 0.8;
	
	// Draw grid
	vec2 q = floor(20.0-uv*10.0);
	float f = mod(q.x+q.y,2.0);
	v -= f*0.1;
	
	// Draw guide lines
	float l = step(0.008,abs(0.4-distance(vec2(0.5), uv)));
	l *= step(0.008,abs(uv.x-0.5));
	l *= step(0.008,abs(uv.y-0.5));
	v = v*l + (1.0-l)*0.5;
	
	// Draw SIN and COS points
	float t = step(0.05,distance(vec2(0.5,s*0.4+0.5), uv));
	t *= step(0.05,distance(vec2(c*0.4+0.5,0.5), uv));
	v = v*t + (1.0-t)*0.3;
	
	set = vec3(v);
}


void trig( inout vec3 set, in vec2 uv, inout Debug dbg ) {
	float s = sin(TIME/1.0);
	float c = cos(TIME/1.0);
	
	// Scale and floor the values for readability
	dbgFloat(dbg,floor(s*100.0)/10.0);
	dbgSpacer(dbg);
	dbgFloat(dbg,floor(c*100.0)/10.0);
	
	draw_canvas(set,uv,s,c);
}


void fragment() {
	vec4 set = vec4(1.0);
	
	Debug dbg = debug_construct(UV);
	trig(set.rgb,UV,dbg);
	debug_finish(set.rgb,dbg);
	
	COLOR = set;
}
Tags
Debug, Editor, Script
The shader code and all code snippets in this post are under CC0 license and can be used freely without the author's permission. Images and videos, and assets depicted in those, do not fall under this license. For more info, see our License terms.

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reid
3 months ago

cool