Improved algorithm for mitre joints on thick lines

imgui_demo.cpp

@@ -4095,6 +4095,7 @@ static void ShowExampleAppCustomRendering(bool* p_open)
                 draw_list->AddRect(ImVec2(x, y), ImVec2(x + sz, y + sz), col32, 10.0f, ImDrawCornerFlags_All, th); x += sz + spacing;
                 draw_list->AddRect(ImVec2(x, y), ImVec2(x + sz, y + sz), col32, 10.0f, ImDrawCornerFlags_TopLeft | ImDrawCornerFlags_BotRight, th); x += sz + spacing;
                 draw_list->AddTriangle(ImVec2(x + sz*0.5f, y), ImVec2(x + sz, y + sz - 0.5f), ImVec2(x, y + sz - 0.5f), col32, th); x += sz + spacing;
+                draw_list->AddTriangle(ImVec2(x + sz*0.5f, y), ImVec2(x + sz*0.6f, y + sz - 0.5f), ImVec2(x + sz*0.4f, y + sz - 0.5f), col32, th); x += sz + spacing;
                 draw_list->AddLine(ImVec2(x, y), ImVec2(x + sz, y), col32, th); x += sz + spacing;                  // Horizontal line (note: drawing a filled rectangle will be faster!)
                 draw_list->AddLine(ImVec2(x, y), ImVec2(x, y + sz), col32, th); x += spacing;                       // Vertical line (note: drawing a filled rectangle will be faster!)
                 draw_list->AddLine(ImVec2(x, y), ImVec2(x + sz, y + sz), col32, th); x += sz + spacing;             // Diagonal line
@@ -4108,6 +4109,7 @@ static void ShowExampleAppCustomRendering(bool* p_open)
             draw_list->AddRectFilled(ImVec2(x, y), ImVec2(x + sz, y + sz), col32, 10.0f); x += sz + spacing;
             draw_list->AddRectFilled(ImVec2(x, y), ImVec2(x + sz, y + sz), col32, 10.0f, ImDrawCornerFlags_TopLeft | ImDrawCornerFlags_BotRight); x += sz + spacing;
             draw_list->AddTriangleFilled(ImVec2(x + sz*0.5f, y), ImVec2(x + sz, y + sz - 0.5f), ImVec2(x, y + sz - 0.5f), col32); x += sz + spacing;
+            draw_list->AddTriangleFilled(ImVec2(x + sz*0.5f, y), ImVec2(x + sz*0.6f, y + sz - 0.5f), ImVec2(x + sz*0.4f, y + sz - 0.5f), col32); x += sz + spacing;
             draw_list->AddRectFilled(ImVec2(x, y), ImVec2(x + sz, y + thickness), col32); x += sz + spacing;        // Horizontal line (faster than AddLine, but only handle integer thickness)
             draw_list->AddRectFilled(ImVec2(x, y), ImVec2(x + thickness, y + sz), col32); x += spacing + spacing;   // Vertical line (faster than AddLine, but only handle integer thickness)
             draw_list->AddRectFilled(ImVec2(x, y), ImVec2(x + 1, y + 1), col32);          x += sz;                  // Pixel (faster than AddLine)

imgui_draw.cpp

@@ -664,6 +664,7 @@ void ImDrawList::PrimQuadUV(const ImVec2& a, const ImVec2& b, const ImVec2& c, c
 // Those macros expects l-values.
 #define IM_NORMALIZE2F_OVER_ZERO(VX,VY)                         { float d2 = VX*VX + VY*VY; if (d2 > 0.0f) { float inv_len = 1.0f / ImSqrt(d2); VX *= inv_len; VY *= inv_len; } }
 #define IM_NORMALIZE2F_OVER_EPSILON_CLAMP(VX,VY,EPS,INVLENMAX)  { float d2 = VX*VX + VY*VY; if (d2 > EPS)  { float inv_len = 1.0f / ImSqrt(d2); if (inv_len > INVLENMAX) inv_len = INVLENMAX; VX *= inv_len; VY *= inv_len; } }
+#define IM_FIXNORMAL2F(VX,VY)                                   { float d2 = VX*VX + VY*VY; if (d2 < 0.5f) d2 = 0.5f; float inv_lensq = 1.0f / d2; VX *= inv_lensq; VY *= inv_lensq; }
 
 // TODO: Thickness anti-aliased lines cap are missing their AA fringe.
 // We avoid using the ImVec2 math operators here to reduce cost to a minimum for debug/non-inlined builds.
@@ -725,7 +726,7 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
                 // Average normals
                 float dm_x = (temp_normals[i1].x + temp_normals[i2].x) * 0.5f;
                 float dm_y = (temp_normals[i1].y + temp_normals[i2].y) * 0.5f;
-                IM_NORMALIZE2F_OVER_EPSILON_CLAMP(dm_x, dm_y, 0.000001f, 100.0f)
+                IM_FIXNORMAL2F(dm_x, dm_y)
                 dm_x *= AA_SIZE;
                 dm_y *= AA_SIZE;
 
@@ -780,7 +781,7 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
                 // Average normals
                 float dm_x = (temp_normals[i1].x + temp_normals[i2].x) * 0.5f;
                 float dm_y = (temp_normals[i1].y + temp_normals[i2].y) * 0.5f;
-                IM_NORMALIZE2F_OVER_EPSILON_CLAMP(dm_x, dm_y, 0.000001f, 100.0f);
+                IM_FIXNORMAL2F(dm_x, dm_y);
                 float dm_out_x = dm_x * (half_inner_thickness + AA_SIZE);
                 float dm_out_y = dm_y * (half_inner_thickness + AA_SIZE);
                 float dm_in_x = dm_x * half_inner_thickness;
@@ -900,7 +901,7 @@ void ImDrawList::AddConvexPolyFilled(const ImVec2* points, const int points_coun
             const ImVec2& n1 = temp_normals[i1];
             float dm_x = (n0.x + n1.x) * 0.5f;
             float dm_y = (n0.y + n1.y) * 0.5f;
-            IM_NORMALIZE2F_OVER_EPSILON_CLAMP(dm_x, dm_y, 0.000001f, 100.0f);
+            IM_FIXNORMAL2F(dm_x, dm_y);
             dm_x *= AA_SIZE * 0.5f;
             dm_y *= AA_SIZE * 0.5f;