Fix collisions. Switch to No-Culling Shadow Maps. Introduce Better Shadow Bias Calculation. Calculate Normals in the Shader.

main.c

@@ -3974,6 +3974,21 @@ void dbg3dline(Vec3 from, Vec3 to)
 	dbgline(from_screenspace, to_screenspace);
 }
 
+void dbg3dline2d(Vec2 a, Vec2 b)  {
+	Vec3 a_3 = V3(a.x, 0.0, a.y);
+	Vec3 b_3 = V3(b.x, 0.0, b.y);
+
+	dbg3dline(a_3, b_3);
+}
+
+void dbg3dline2dOffset(Vec2 a, Vec2 offset)  {
+	Vec3 a_3 = V3(a.x, 0.0, a.y);
+	Vec3 b_3 = V3(offset.x, 0.0, offset.y);
+
+	dbg3dline(a_3, AddV3(a_3,b_3));
+}
+
+
 void colorquadplane(Quad q, Color col)
 {
 	Quad warped = {0};
@@ -4223,6 +4238,41 @@ typedef struct MoveSlideParams
 } MoveSlideParams;
 
 
+Vec2 get_penetration_vector(AABB stable, AABB dynamic)
+{
+	//Assumes we already know that they are colliding.
+	//It could be faster to use this info for collision detection as well,
+	//but this would require an intrusive refactor, and it is not the common
+	//case that things are colliding anyway, so it's actually not that much
+	//duplicated work.
+	Vec2 dynamic_centre = aabb_center(dynamic);
+	Vec2 dynamic_half_dims = MulV2F(aabb_size(dynamic), 0.5f);
+
+	stable.lower_right.x += dynamic_half_dims.x;
+	stable.lower_right.y -= dynamic_half_dims.y;
+	stable.upper_left.x  -= dynamic_half_dims.x;
+	stable.upper_left.y  += dynamic_half_dims.y;
+
+	float right_delta  = stable.lower_right.x - dynamic_centre.x;
+	float left_delta   = stable.upper_left.x  - dynamic_centre.x;
+	float bottom_delta = stable.lower_right.y - dynamic_centre.y;
+	float top_delta    = stable.upper_left.y  - dynamic_centre.y;
+
+	float r = fabsf( right_delta);
+	float l = fabsf(  left_delta);
+	float b = fabsf(bottom_delta);
+	float t = fabsf(   top_delta);
+
+	if (r <= l && r <= b && r <= t)
+		return V2(right_delta, 0.0);
+	if (left_delta <= r && l <= b && l <= t)
+		return V2(left_delta, 0.0);
+	if (b <= r && b <= l && b <= t)
+		return V2(0.0, bottom_delta);
+	return V2(0.0, top_delta);
+}
+
+
 // returns new pos after moving and sliding against collidable things
 Vec2 move_and_slide(MoveSlideParams p)
 {
@@ -4328,43 +4378,12 @@ Vec2 move_and_slide(MoveSlideParams p)
 		BUFF_ITER(CollisionObj, &overlapping_smallest_first)
 		{
 			AABB to_depenetrate_from = it->aabb;
-			int iters_tried_to_push_apart = 0;
-			bool happened_with_this_one = false;
-			while (overlapping(to_depenetrate_from, at_new) && iters_tried_to_push_apart < 500)
-			{
-				happened_with_this_one = true;
-				const float move_dist = 0.01f;
-
-				info.happened = true;
-				Vec2 from_point = aabb_center(to_depenetrate_from);
-				Vec2 to_player = NormV2(SubV2(aabb_center(at_new), from_point));
-				Vec2 compass_dirs[4] = {
-					V2(1.0, 0.0),
-					V2(-1.0, 0.0),
-					V2(0.0,  1.0),
-					V2(0.0, -1.0),
-				};
-				int closest_index = -1;
-				float closest_dot = -99999999.0f;
-				for (int i = 0; i < 4; i++)
-				{
-					float dot = DotV2(compass_dirs[i], to_player);
-					if (dot > closest_dot)
-					{
-						closest_index = i;
-						closest_dot = dot;
-					}
-				}
-				// sometimes when objects are perfectly overlapping, every dot product is negative infinity
-				if(closest_index == -1) closest_index = 0;
-				Vec2 move_dir = compass_dirs[closest_index];
-				info.normal = move_dir;
-				dbgplanevec(from_point, MulV2F(move_dir, 30.0f));
-				Vec2 move = MulV2F(move_dir, move_dist);
-				at_new.upper_left = AddV2(at_new.upper_left, move);
-				at_new.lower_right = AddV2(at_new.lower_right, move);
-				iters_tried_to_push_apart++;
-			}
+
+			Vec2 resolution_vector = get_penetration_vector(to_depenetrate_from, at_new);
+			at_new.upper_left  = AddV2(at_new.upper_left , resolution_vector);
+			at_new.lower_right = AddV2(at_new.lower_right, resolution_vector);
+			bool happened_with_this_one = true;
+
 			if(happened_with_this_one)
 			{
 				bool already_in_happened = false;
@@ -4680,7 +4699,7 @@ void draw_dialog_panel(Entity *talking_to, float alpha)
 		line(AddV2(dialog_quad.lr, V2(line_width, 0.0)), AddV2(dialog_quad.ll, V2(-line_width, 0.0)), line_width, line_color);
 		line(dialog_quad.ll, dialog_quad.ul, line_width, line_color);
 
-		float padding = 5.0f;
+		float padding = 7.5f;
 		dialog_panel.upper_left = AddV2(dialog_panel.upper_left, V2(padding, -padding));
 		dialog_panel.lower_right = AddV2(dialog_panel.lower_right, V2(-padding, padding));
 
@@ -4945,7 +4964,7 @@ Shadow_State init_shadow_state() {
         },
         .shader = sg_make_shader(shadow_mapper_program_shader_desc(sg_query_backend())),
         // Cull front faces in the shadow map pass
-        .cull_mode = SG_CULLMODE_FRONT,
+        // .cull_mode = SG_CULLMODE_BACK,
         .sample_count = 1,
         .depth = {
             .pixel_format = SG_PIXELFORMAT_DEPTH,
@@ -5078,6 +5097,7 @@ Shadow_Volume_Params calculate_shadow_volume_params(Vec3 light_dir)
 	return result;
 }
 
+
 void frame(void)
 {
 	static float speed_factor = 1.0f;

threedee.glsl

@@ -7,7 +7,8 @@ in vec2 uv_in;
 out vec3 pos;
 out vec2 uv;
 out vec4 light_space_fragment_position;
-
+out vec3 light_dir;
+out vec4 world_space_frag_pos;
 
 uniform vs_params {
 	mat4 model;
@@ -20,10 +21,13 @@ void main() {
 	pos = pos_in;
 	uv = uv_in;
 
-	vec4 world_space_frag_pos = model * vec4(pos_in, 1.0);
+	world_space_frag_pos = model * vec4(pos_in, 1.0);
 	vec4 frag_pos = view * world_space_frag_pos;
 	gl_Position = projection * frag_pos;
 
+	//@Speed I think we can just take the third row here and be fine.
+	light_dir = normalize(inverse(directional_light_space_matrix) * vec4(0.0, 0.0, -1.0, 0.0)).xyz;
+
 	light_space_fragment_position = directional_light_space_matrix * vec4(world_space_frag_pos.xyz, 1.0);
 }
 @end
@@ -40,6 +44,8 @@ uniform fs_params {
 in vec3 pos;
 in vec2 uv;
 in vec4 light_space_fragment_position;
+in vec3 light_dir;
+in vec4 world_space_frag_pos;
 
 out vec4 frag_color;
 
@@ -47,7 +53,7 @@ float decodeDepth(vec4 rgba) {
     return dot(rgba, vec4(1.0, 1.0/255.0, 1.0/65025.0, 1.0/16581375.0));
 }
 
-float do_shadow_sample(sampler2D shadowMap, vec2 uv, float scene_depth) {
+float do_shadow_sample(sampler2D shadowMap, vec2 uv, float scene_depth, float n_dot_l) {
 	{
 		//WebGL does not support GL_CLAMP_TO_BORDER, or border colors at all it seems, so we have to check explicitly.
 		//This will probably slow down other versions which do support texture borders, but the current system does
@@ -56,12 +62,21 @@ float do_shadow_sample(sampler2D shadowMap, vec2 uv, float scene_depth) {
 			return 1.0;
 	}
 	float map_depth = decodeDepth(texture(shadowMap, uv));
-	map_depth += 0.001;//bias to counter self-shadowing
+
+    // float bias = max(0.03f * (1.0f - n_dot_l), 0.005f);
+    // bias = clamp(bias, 0.0, 0.01);
+
+	float offset_scale_N = sqrt(1 - n_dot_l*n_dot_l);
+	float offset_scale_L = offset_scale_N / n_dot_l;
+	float bias = 0.0002 * offset_scale_N + 0.0001 * offset_scale_L;
+
+	map_depth += bias;
+
     return step(scene_depth, map_depth);
 }
 
 
-float bilinear_shadow_sample(sampler2D shadowMap, vec2 uv, int texture_width, int texture_height, float scene_depth_light_space) {
+float bilinear_shadow_sample(sampler2D shadowMap, vec2 uv, int texture_width, int texture_height, float scene_depth_light_space, float n_dot_l) {
 	vec2 texture_dim = vec2(float(texture_width), float(texture_height));
 	vec2 texel_dim  = vec2(1.0 / float(texture_width ), 1.0 / float(texture_height));
 
@@ -75,10 +90,10 @@ float bilinear_shadow_sample(sampler2D shadowMap, vec2 uv, int texture_width, in
 	vec2 uv_2 = vec2(texel_uv_floor.x, texel_uv_ceil.y );
 	vec2 uv_3 = vec2(texel_uv_ceil.x , texel_uv_ceil.y );
 
-	float bl = do_shadow_sample(shadowMap, uv_0, scene_depth_light_space);
-	float br = do_shadow_sample(shadowMap, uv_1, scene_depth_light_space);
-	float tl = do_shadow_sample(shadowMap, uv_2, scene_depth_light_space);
-	float tr = do_shadow_sample(shadowMap, uv_3, scene_depth_light_space);
+	float bl = do_shadow_sample(shadowMap, uv_0, scene_depth_light_space, n_dot_l);
+	float br = do_shadow_sample(shadowMap, uv_1, scene_depth_light_space, n_dot_l);
+	float tl = do_shadow_sample(shadowMap, uv_2, scene_depth_light_space, n_dot_l);
+	float tr = do_shadow_sample(shadowMap, uv_3, scene_depth_light_space, n_dot_l);
 
 	vec2 interp = fract(texel_uv);
 
@@ -89,7 +104,7 @@ float bilinear_shadow_sample(sampler2D shadowMap, vec2 uv, int texture_width, in
 	return result;
 }
 
-float calculate_shadow_factor(sampler2D shadowMap, vec4 light_space_fragment_position) {
+float calculate_shadow_factor(sampler2D shadowMap, vec4 light_space_fragment_position, float n_dot_l) {
 	float shadow = 1.0;
 
     vec3 projected_coords = light_space_fragment_position.xyz / light_space_fragment_position.w;
@@ -109,11 +124,13 @@ float calculate_shadow_factor(sampler2D shadowMap, vec4 light_space_fragment_pos
         for (int y=-2; y<=2; y++) {
             vec2 off = vec2(x*texel_step_size, y*texel_step_size);
 			// shadow += do_shadow_sample(shadowMap, shadow_uv+off, current_depth);
-            shadow += bilinear_shadow_sample(shadowMap, shadow_uv+off, shadow_map_dimension, shadow_map_dimension, current_depth);
+            shadow += bilinear_shadow_sample(shadowMap, shadow_uv+off, shadow_map_dimension, shadow_map_dimension, current_depth, n_dot_l);
         }
     }
     shadow /= 25.0;
 
+
+
 	return shadow;
 }
 
@@ -126,12 +143,17 @@ void main() {
 	}
 	else
 	{
-		vec3 light_dir = normalize(vec3(1, -1, 0));
 
-		float shadow_factor = calculate_shadow_factor(shadow_map, light_space_fragment_position);
-		shadow_factor = shadow_factor * 0.5 + 0.5;
+		vec3 normal = normalize(cross(dFdx(world_space_frag_pos.xyz), dFdy(world_space_frag_pos.xyz)));
+
+		float n_dot_l = clamp(dot(normal, light_dir), 0.0, 1.0);
+		float shadow_factor = calculate_shadow_factor(shadow_map, light_space_fragment_position, n_dot_l);
+
+		float lighting_factor = shadow_factor * n_dot_l;
+		lighting_factor = lighting_factor * 0.5 + 0.5;
+
+		frag_color = vec4(col.rgb*lighting_factor, 1.0);
 	
-		frag_color = vec4(col.rgb*shadow_factor, 1.0);
 	}
 }
 @end