diff --git a/imgui_demo.cpp b/imgui_demo.cpp index 4e233a45..7264da37 100644 --- a/imgui_demo.cpp +++ b/imgui_demo.cpp @@ -7618,47 +7618,180 @@ static void ShowExampleAppCustomRendering(bool* p_open) if (ImGui::BeginTabItem("Shadows")) { static float shadow_thickness = 40.0f; - static bool shadow_filled = false; static ImVec4 shadow_color = ImVec4(0.0f, 0.0f, 0.0f, 1.0f); - static ImVec4 shape_color = ImVec4(0.9f, 0.0f, 0.0f, 1.0f); + static bool shadow_filled = false; + static ImVec4 shape_color = ImVec4(0.9f, 0.6f, 0.3f, 1.0f); static float shape_rounding = 0.0f; - static ImVec4 bg_color = ImVec4(1.0f, 1.0f, 1.0f, 1.0f); + static ImVec2 shadow_offset(0.0f, 0.0f); + static ImVec4 background_color = ImVec4(0.5f, 0.5f, 0.7f, 1.0f); + static bool wireframe = false; + static bool aa = true; + static int poly_shape_index = 0; ImGui::Checkbox("Shadow filled", &shadow_filled); ImGui::SameLine(); HelpMarker("This will fill the section behind the shape to shadow. It's often unnecessary and wasteful but provided for consistency."); + ImGui::Checkbox("Wireframe shapes", &wireframe); + ImGui::SameLine(); + HelpMarker("This draws the shapes in wireframe so you can see the shadow underneath."); + ImGui::Checkbox("Anti-aliasing", &aa); ImGui::DragFloat("Shadow Thickness", &shadow_thickness, 1.0f, 0.0f, 100.0f, "%.02f"); + ImGui::SliderFloat2("Offset", (float*)&shadow_offset, -32.0f, 32.0f); + ImGui::SameLine(); + HelpMarker("Note that currently circles/convex shapes do not support non-zero offsets for unfilled shadows."); + ImGui::ColorEdit4("Background Color", &background_color.x); ImGui::ColorEdit4("Shadow Color", &shadow_color.x); ImGui::ColorEdit4("Shape Color", &shape_color.x); ImGui::DragFloat("Shape Rounding", &shape_rounding, 1.0f, 0.0f, 20.0f, "%.02f"); - ImGui::ColorEdit4("Background Color", &bg_color.x); + ImGui::Combo("Convex shape", &poly_shape_index, "Shape 1\0Shape 2\0Shape 3\0Shape 4\0Shape 4 (winding reversed)"); ImDrawList* draw_list = ImGui::GetWindowDrawList(); + ImDrawListFlags old_flags = draw_list->Flags; + + if (aa) + draw_list->Flags |= ~ImDrawListFlags_AntiAliasedFill; + else + draw_list->Flags &= ~ImDrawListFlags_AntiAliasedFill; + + // Fill a strip of background + draw_list->AddRectFilled(ImVec2(ImGui::GetCursorScreenPos().x, ImGui::GetCursorScreenPos().y), ImVec2(ImGui::GetCursorScreenPos().x + ImGui::GetWindowContentRegionMax().x, ImGui::GetCursorScreenPos().y + 200.0f), ImGui::GetColorU32(background_color)); + + // Rectangle { ImVec2 p = ImGui::GetCursorScreenPos(); ImVec2 r1(p.x + 50.0f, p.y + 50.0f); ImVec2 r2(p.x + 150.0f, p.y + 150.0f); - draw_list->AddRectFilled(p, ImVec2(p.x + 200.0f, p.y + 200.0f), ImGui::GetColorU32(bg_color)); if (shadow_filled) - draw_list->AddShadowRectFilled(r1, r2, shadow_thickness, ImVec2(0.0f, 0.0f), ImGui::GetColorU32(shadow_color)); + draw_list->AddShadowRectFilled(r1, r2, shadow_thickness, shadow_offset, ImGui::GetColorU32(shadow_color)); else - draw_list->AddShadowRect(r1, r2, shadow_thickness, ImVec2(0.0f, 0.0f), ImGui::GetColorU32(shadow_color), shape_rounding); - draw_list->AddRectFilled(r1, r2, ImGui::GetColorU32(shape_color), shape_rounding); + draw_list->AddShadowRect(r1, r2, shadow_thickness, shadow_offset, ImGui::GetColorU32(shadow_color), shape_rounding); + if (wireframe) + draw_list->AddRect(r1, r2, ImGui::GetColorU32(shape_color), shape_rounding); + else + draw_list->AddRectFilled(r1, r2, ImGui::GetColorU32(shape_color), shape_rounding); ImGui::Dummy(ImVec2(200.0f, 200.0f)); } + + ImGui::SameLine(); + + // Circle { ImVec2 p = ImGui::GetCursorScreenPos(); - ImVec2 center(p.x + 100.0f, p.y + 100.0f); - float radius = 50.0f; - draw_list->AddRectFilled(p, ImVec2(p.x + 200.0f, p.y + 200.0f), ImGui::GetColorU32(bg_color)); + float off = 10.0f; + ImVec2 r1(p.x + 50.0f + off, p.y + 50.0f + off); + ImVec2 r2(p.x + 150.0f - off, p.y + 150.0f - off); + ImVec2 c(p.x + 100.0f, p.y + 100.0f); if (shadow_filled) - draw_list->AddShadowCircleFilled(center, radius, shadow_thickness, ImVec2(0.0f, 0.0f), ImGui::GetColorU32(shadow_color), 0); + draw_list->AddShadowCircleFilled(c, 50.0f, shadow_thickness, shadow_offset, ImGui::GetColorU32(shadow_color)); else - draw_list->AddShadowCircle(center, radius, shadow_thickness, ImVec2(0.0f, 0.0f), ImGui::GetColorU32(shadow_color), 0); - draw_list->AddCircleFilled(center, radius, ImGui::GetColorU32(shape_color), 0); + draw_list->AddShadowCircle(c, 50.0f, shadow_thickness, ImVec2(0.0f, 0.0f), ImGui::GetColorU32(shadow_color)); // Offset forced to zero here because it isn't supported + if (wireframe) + draw_list->AddCircle(c, 50.0f, ImGui::GetColorU32(shape_color), 0); + else + draw_list->AddCircleFilled(c, 50.0f, ImGui::GetColorU32(shape_color), 0); ImGui::Dummy(ImVec2(200.0f, 200.0f)); } + ImGui::SameLine(); + + // Convex shape + { + ImVec2 pos = ImGui::GetCursorScreenPos(); + + const ImVec2 poly_centre(pos.x + 50.0f, pos.y + 100.0f); + ImVec2* poly_points; + int num_poly_points; + + switch (poly_shape_index) + { + default: + case 0: + { + ImVec2 poly_point_data[] = + { + ImVec2(poly_centre.x - 32.0f, poly_centre.y), + ImVec2(poly_centre.x - 24.0f, poly_centre.y + 24.0f), + ImVec2(poly_centre.x, poly_centre.y + 32.0f), + ImVec2(poly_centre.x + 24.0f, poly_centre.y + 24.0f), + ImVec2(poly_centre.x + 32.0f, poly_centre.y), + ImVec2(poly_centre.x + 24.0f, poly_centre.y - 24.0f), + ImVec2(poly_centre.x, poly_centre.y - 32.0f), + ImVec2(poly_centre.x - 32.0f, poly_centre.y - 32.0f) + }; + poly_points = poly_point_data; + num_poly_points = 8; + break; + } + case 1: + { + ImVec2 poly_point_data[] = + { + ImVec2(poly_centre.x + 40.0f, poly_centre.y - 20.0f), + ImVec2(poly_centre.x, poly_centre.y + 32.0f), + ImVec2(poly_centre.x - 24.0f, poly_centre.y - 32.0f) + }; + poly_points = poly_point_data; + num_poly_points = 3; + break; + } + case 2: + { + ImVec2 poly_point_data[] = + { + ImVec2(poly_centre.x - 32.0f, poly_centre.y), + ImVec2(poly_centre.x, poly_centre.y + 32.0f), + ImVec2(poly_centre.x + 32.0f, poly_centre.y), + ImVec2(poly_centre.x, poly_centre.y - 32.0f) + }; + poly_points = poly_point_data; + num_poly_points = 4; + break; + } + case 3: + { + ImVec2 poly_point_data[] = + { + ImVec2(poly_centre.x - 4.0f, poly_centre.y - 20.0f), + ImVec2(poly_centre.x + 12.0f, poly_centre.y + 2.0f), + ImVec2(poly_centre.x + 8.0f, poly_centre.y + 16.0f), + ImVec2(poly_centre.x, poly_centre.y + 32.0f), + ImVec2(poly_centre.x - 16.0f, poly_centre.y - 32.0f) + }; + poly_points = poly_point_data; + num_poly_points = 5; + break; + } + case 4: // Same as test case 3 but with reversed winding + { + ImVec2 poly_point_data[] = + { + ImVec2(poly_centre.x - 16.0f, poly_centre.y - 32.0f), + ImVec2(poly_centre.x, poly_centre.y + 32.0f), + ImVec2(poly_centre.x + 8.0f, poly_centre.y + 16.0f), + ImVec2(poly_centre.x + 12.0f, poly_centre.y + 2.0f), + ImVec2(poly_centre.x - 4.0f, poly_centre.y - 20.0f) + }; + poly_points = poly_point_data; + num_poly_points = 5; + break; + } + } + + if (shadow_filled) + draw_list->AddShadowConvexPolyFilled(poly_points, num_poly_points, shadow_thickness, shadow_offset, ImGui::GetColorU32(shadow_color)); + else + draw_list->AddShadowConvexPoly(poly_points, num_poly_points, shadow_thickness, ImVec2(0.0f, 0.0f), ImGui::GetColorU32(shadow_color)); // Offset forced to zero because it isn't supported + + if (wireframe) + draw_list->AddPolyline(poly_points, num_poly_points, ImGui::GetColorU32(shape_color), true, 1.0f); + else + draw_list->AddConvexPolyFilled(poly_points, num_poly_points, ImGui::GetColorU32(shape_color)); + + ImGui::Dummy(ImVec2(200.0f, 200.0f)); + } + + draw_list->Flags = old_flags; + ImGui::EndTabItem(); } diff --git a/imgui_draw.cpp b/imgui_draw.cpp index f1e33db6..d5adb47f 100644 --- a/imgui_draw.cpp +++ b/imgui_draw.cpp @@ -2168,7 +2168,15 @@ void ImDrawList::AddShadowRect(const ImVec2& p_min, const ImVec2& p_max, float s // Add a shadow for a convex shape described by points and num_points static void AddShadowConvexShapeEx(ImDrawList* draw_list, const ImVec2* points, int num_points, float shadow_thickness, const ImVec2& offset, ImU32 col, bool is_filled) { - IM_UNUSED(offset); // Offset not currently supported + IM_ASSERT((is_filled || (ImLengthSqr(offset) < 0.00001f)) && "Drawing circle/convex shape shadows with no center fill and an offset is not currently supported"); + IM_ASSERT(num_points >= 3); + + // Calculate poly vertex order + int vertex_winding = (((points[0].x * (points[1].y - points[2].y)) + (points[1].x * (points[2].y - points[0].y)) + (points[2].x * (points[0].y - points[1].y))) < 0.0f) ? -1 : 1; + + // If we're using anti-aliasing, then inset the shadow by 0.5 pixels to avoid unpleasant fringing artifacts + const bool use_inset_distance = (draw_list->Flags & ImDrawListFlags_AntiAliasedFill) && (!is_filled); + const float inset_distance = 0.5f; const ImVec4 uvs = draw_list->_Data->ShadowRectUvs[9]; @@ -2191,16 +2199,54 @@ static void AddShadowConvexShapeEx(ImDrawList* draw_list, const ImVec2* points, // Normalize a vector #define NORMALIZE(vec) ((vec) / ImLength((vec), 0.001f)) + const int required_stack_mem = (num_edges * sizeof(ImVec2)) + (num_edges * sizeof(float)); + const ImU8* base_mem_for_normals_and_edges = (ImU8*)alloca(required_stack_mem); + ImU8* mem_for_normals_and_edges = (ImU8*)base_mem_for_normals_and_edges; + // Calculate edge normals - ImVec2* edge_normals = (ImVec2*)alloca(num_edges * sizeof(ImVec2)); + ImVec2* edge_normals = (ImVec2*)mem_for_normals_and_edges; + mem_for_normals_and_edges += num_edges * sizeof(ImVec2); for (int edge_index = 0; edge_index < num_edges; edge_index++) { - ImVec2 edge_start = points[edge_index]; + ImVec2 edge_start = points[edge_index]; // No need to apply offset here because the normal is unaffected ImVec2 edge_end = points[(edge_index + 1) % num_edges]; ImVec2 edge_normal = NORMALIZE(ImVec2(edge_end.y - edge_start.y, -(edge_end.x - edge_start.x))); - edge_normals[edge_index] = edge_normal; + edge_normals[edge_index] = edge_normal * (float)vertex_winding; // Flip normals for reverse winding + } + + // Pre-calculate edge scales + // We need to do this because we need the edge strips to have widths that match up with the corner sections, otherwise pixel cracking can occur along the boundaries + float* edge_size_scales = (float*)mem_for_normals_and_edges; + mem_for_normals_and_edges += num_edges * sizeof(float); + IM_ASSERT_PARANOID(mem_for_normals_and_edges == (base_mem_for_normals_and_edges + required_stack_mem)); // Check we used exactly what we allocated + + { + ImVec2 prev_edge_normal = edge_normals[num_edges - 1]; + + for (int edge_index = 0; edge_index < num_edges; edge_index++) + { + ImVec2 edge_normal = edge_normals[edge_index]; + float cos_angle_coverage = ImDot(edge_normal, prev_edge_normal); + + if (cos_angle_coverage < 0.999999f) + { + float angle_coverage = ImAcos(cos_angle_coverage); + + // If we are covering more than 90 degrees we need an intermediate vertex to stop the required expansion tending towards infinity, and thus the effective angle will be halved + if (cos_angle_coverage <= 0.0f) + angle_coverage *= 0.5f; + + edge_size_scales[edge_index] = 1.0f / ImCos(angle_coverage * 0.5f); // How much we need to expand our size by to avoid clipping the corner of the texture off + } + else + { + edge_size_scales[edge_index] = 1.0f; // No corner, thus default scale + } + + prev_edge_normal = edge_normal; + } } const int max_vertices = (4 + (3 * 2) + (is_filled ? 1 : 0)) * num_edges; // 4 vertices per edge plus 3*2 for potentially two corner triangles, plus one per vertex for fill @@ -2210,14 +2256,22 @@ static void AddShadowConvexShapeEx(ImDrawList* draw_list, const ImVec2* points, ImDrawVert* vtx_write = draw_list->_VtxWritePtr; ImDrawIdx current_idx = (ImDrawIdx)draw_list->_VtxCurrentIdx; - //ImVec2 previous_edge_start = points[0]; - ImVec2 edge_start = points[0]; + ImVec2 previous_edge_start = points[0] + offset; ImVec2 prev_edge_normal = edge_normals[num_edges - 1]; + ImVec2 edge_start = points[0] + offset; + + if (use_inset_distance) + edge_start -= NORMALIZE(edge_normals[0] + prev_edge_normal) * inset_distance; for (int edge_index = 0; edge_index < num_edges; edge_index++) - { - const ImVec2 edge_end = points[(edge_index + 1) % num_edges]; + { + ImVec2 edge_end = points[(edge_index + 1) % num_edges] + offset; ImVec2 edge_normal = edge_normals[edge_index]; + const float size_scale_start = edge_size_scales[edge_index]; + const float size_scale_end = edge_size_scales[(edge_index + 1) % num_edges]; + + if (use_inset_distance) + edge_end -= NORMALIZE(edge_normals[(edge_index + 1) % num_edges] + edge_normal) * inset_distance; // Add corner section float cos_angle_coverage = ImDot(edge_normal, prev_edge_normal); @@ -2241,14 +2295,12 @@ static void AddShadowConvexShapeEx(ImDrawList* draw_list, const ImVec2* points, // Calculate UV for the section of the curved texture - float angle_coverage = ImAcos(cos_angle_coverage); - float sin_angle_coverage = ImSin(angle_coverage); - - float size_scale = 1.0f / ImCos(angle_coverage * 0.5f); // How much we need to expand our size by to avoid clipping the corner of the texture off + const float angle_coverage = ImAcos(cos_angle_coverage); + const float sin_angle_coverage = ImSin(angle_coverage); ImVec2 edge_delta = solid_to_edge_delta_texels; - edge_delta *= size_scale; + edge_delta *= size_scale_start; ImVec2 rotated_edge_delta = ImVec2((edge_delta.x * cos_angle_coverage) + (edge_delta.y * sin_angle_coverage), (edge_delta.x * sin_angle_coverage) + (edge_delta.y * cos_angle_coverage)); @@ -2261,7 +2313,7 @@ static void AddShadowConvexShapeEx(ImDrawList* draw_list, const ImVec2* points, ImVec2 expanded_edge_uv = solid_uv + edge_delta; ImVec2 other_edge_uv = solid_uv + rotated_edge_delta; // Rotated UV to encompass the necessary section of the curve - float expanded_thickness = shadow_thickness * size_scale; + float expanded_thickness = shadow_thickness * size_scale_start; // Add a triangle to fill the corner ImVec2 outer_edge_start = edge_start + (prev_edge_normal * expanded_thickness); @@ -2285,14 +2337,17 @@ static void AddShadowConvexShapeEx(ImDrawList* draw_list, const ImVec2* points, if (edge_length > 0.00001f) // Don't try and process degenerate edges { - ImVec2 outer_edge_start = edge_start + (edge_normal * shadow_thickness); - ImVec2 outer_edge_end = edge_end + (edge_normal * shadow_thickness); + ImVec2 outer_edge_start = edge_start + (edge_normal * shadow_thickness * size_scale_start); + ImVec2 outer_edge_end = edge_end + (edge_normal * shadow_thickness * size_scale_end); + + ImVec2 scaled_edge_uv_start = solid_uv + ((edge_uv - solid_uv) * size_scale_start); + ImVec2 scaled_edge_uv_end = solid_uv + ((edge_uv - solid_uv) * size_scale_end); // Write vertices, inner first, then outer vtx_write->pos = edge_start; vtx_write->col = col; vtx_write->uv = solid_uv; vtx_write++; vtx_write->pos = edge_end; vtx_write->col = col; vtx_write->uv = solid_uv; vtx_write++; - vtx_write->pos = outer_edge_end; vtx_write->col = col; vtx_write->uv = edge_uv; vtx_write++; - vtx_write->pos = outer_edge_start; vtx_write->col = col; vtx_write->uv = edge_uv; vtx_write++; + vtx_write->pos = outer_edge_end; vtx_write->col = col; vtx_write->uv = scaled_edge_uv_end; vtx_write++; + vtx_write->pos = outer_edge_start; vtx_write->col = col; vtx_write->uv = scaled_edge_uv_start; vtx_write++; *(idx_write++) = current_idx; *(idx_write++) = current_idx + 1; @@ -2311,7 +2366,7 @@ static void AddShadowConvexShapeEx(ImDrawList* draw_list, const ImVec2* points, // Add vertices for (int edge_index = 0; edge_index < num_edges; edge_index++) { - vtx_write->pos = points[edge_index]; vtx_write->col = col; vtx_write->uv = solid_uv; vtx_write++; + vtx_write->pos = points[edge_index] + offset; vtx_write->col = col; vtx_write->uv = solid_uv; vtx_write++; } // Add tris @@ -3694,7 +3749,7 @@ static void ImFontAtlasBuildRenderShadowTexData(ImFontAtlas* atlas) for (int x = 0; x < size; x++) { float dist = DistanceFromPoint(ImVec2((float)x, (float)y), center_point); - float alpha = 1.0f - ImMin(ImMax((float)dist /*+ shadow_cfg->TexDistanceFieldOffset*/, 0.0f) / ImMax((float)shadow_cfg->TexCornerSize /*+ shadow_cfg->TexDistanceFieldOffset*/, 0.001f), 1.0f); + float alpha = 1.0f - ImMin(ImMax((float)dist + shadow_cfg->TexDistanceFieldOffset, 0.0f) / ImMax((float)shadow_cfg->TexCornerSize + shadow_cfg->TexDistanceFieldOffset, 0.001f), 1.0f); alpha = ImPow(alpha, shadow_cfg->TexFalloffPower); // Apply power curve to give a nicer falloff tex_data[x + (y * size)] = alpha; }