Adds Canvas2D to encapsulate low level GL calls for 2D rendering.

Implements DrawLine for charts.

Differential Revision: https://code.wildfiregames.com/D4024
This was SVN commit r25588.

source/graphics/Canvas2D.cpp

@@ -0,0 +1,64 @@
+/* Copyright (C) 2021 Wildfire Games.
+ * This file is part of 0 A.D.
+ *
+ * 0 A.D. is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 0 A.D. is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "precompiled.h"
+
+#include "Canvas2D.h"
+
+#include "graphics/Color.h"
+#include "graphics/ShaderManager.h"
+#include "gui/GUIMatrix.h"
+#include "maths/Vector2D.h"
+#include "ps/CStrInternStatic.h"
+#include "renderer/Renderer.h"
+
+void CCanvas2D::DrawLine(const std::vector<CVector2D>& points, const float width, const CColor& color)
+{
+	std::vector<float> vertices;
+	vertices.reserve(points.size() * 3);
+	for (const CVector2D& point : points)
+	{
+		vertices.emplace_back(point.X);
+		vertices.emplace_back(point.Y);
+		vertices.emplace_back(0.0f);
+	}
+
+	// Setup the render state
+	CMatrix3D transform = GetDefaultGuiMatrix();
+	CShaderDefines lineDefines;
+	CShaderTechniquePtr tech = g_Renderer.GetShaderManager().LoadEffect(str_gui_solid, g_Renderer.GetSystemShaderDefines(), lineDefines);
+	tech->BeginPass();
+	CShaderProgramPtr shader = tech->GetShader();
+
+	shader->Uniform(str_transform, transform);
+	shader->Uniform(str_color, color );
+	shader->VertexPointer(3, GL_FLOAT, 0, &vertices[0]);
+	shader->AssertPointersBound();
+
+#if !CONFIG2_GLES
+	glEnable(GL_LINE_SMOOTH);
+#endif
+	glLineWidth(width);
+	if (!g_Renderer.DoSkipSubmit())
+		glDrawArrays(GL_LINE_STRIP, 0, vertices.size() / 3);
+	glLineWidth(1.0f);
+#if !CONFIG2_GLES
+	glDisable(GL_LINE_SMOOTH);
+#endif
+
+	tech->EndPass();
+}

source/graphics/Canvas2D.h

@@ -0,0 +1,35 @@
+/* Copyright (C) 2021 Wildfire Games.
+ * This file is part of 0 A.D.
+ *
+ * 0 A.D. is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 0 A.D. is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef INCLUDED_CANVAS2D
+#define INCLUDED_CANVAS2D
+
+#include "maths/Vector2D.h"
+
+#include <vector>
+
+struct CColor;
+
+// Encapsulates 2D drawing functionality to hide and optimize
+// low level API calls.
+class CCanvas2D
+{
+public:
+	void DrawLine(const std::vector<CVector2D>& points, const float width, const CColor& color);
+};
+
+#endif // INCLUDED_CANVAS2D

source/gui/CGUI.cpp

@@ -19,6 +19,7 @@
 
 #include "CGUI.h"
 
+#include "graphics/Canvas2D.h"
 #include "gui/IGUIScrollBar.h"
 #include "gui/ObjectBases/IGUIObject.h"
 #include "gui/ObjectTypes/CGUIDummyObject.h"
@@ -343,8 +344,10 @@ void CGUI::Draw()
 			return visibleObject1.bufferedZ < visibleObject2.bufferedZ;
 		return visibleObject1.index < visibleObject2.index;
 	});
+
+	CCanvas2D canvas;
 	for (const VisibleObject& visibleObject : visibleObjects)
-		visibleObject.object->Draw();
+		visibleObject.object->Draw(canvas);
 }
 
 void CGUI::DrawSprite(const CGUISpriteInstance& Sprite, const CRect& Rect, const CRect& UNUSED(Clipping))

source/gui/ObjectBases/IGUIObject.h

@@ -37,6 +37,7 @@
 #include <map>
 #include <vector>
 
+class CCanvas2D;
 class CGUI;
 class CGUISize;
 class IGUIObject;
@@ -264,7 +265,7 @@ protected:
 	/**
 	 * Draws the object.
 	 */
-	virtual void Draw() = 0;
+	virtual void Draw(CCanvas2D& canvas) = 0;
 
 	/**
 	 * Some objects need to be able to pre-emptively process SDL_Event_.

source/gui/ObjectTypes/CButton.cpp

@@ -80,7 +80,7 @@ void CButton::HandleMessage(SGUIMessage& Message)
 	IGUITextOwner::HandleMessage(Message);
 }
 
-void CButton::Draw()
+void CButton::Draw(CCanvas2D& UNUSED(canvas))
 {
 	m_pGUI.DrawSprite(
 		GetButtonSprite(m_Sprite, m_SpriteOver, m_SpritePressed, m_SpriteDisabled),

source/gui/ObjectTypes/CButton.h

@@ -56,7 +56,7 @@ public:
 	/**
 	 * Draws the Button
 	 */
-	virtual void Draw();
+	virtual void Draw(CCanvas2D& canvas);
 
 	/**
 	 * @see IGUIObject#IsMouseOver()

source/gui/ObjectTypes/CChart.cpp

@@ -19,6 +19,7 @@
 
 #include "CChart.h"
 
+#include "graphics/Canvas2D.h"
 #include "graphics/ShaderManager.h"
 #include "gui/GUIMatrix.h"
 #include "gui/SettingTypes/CGUIList.h"
@@ -65,24 +66,6 @@ void CChart::HandleMessage(SGUIMessage& Message)
 		UpdateSeries();
 }
 
-void CChart::DrawLine(const CShaderProgramPtr& shader, const CGUIColor& color, const std::vector<float>& vertices) const
-{
-	shader->Uniform(str_color, color);
-	shader->VertexPointer(3, GL_FLOAT, 0, &vertices[0]);
-	shader->AssertPointersBound();
-
-#if !CONFIG2_GLES
-	glEnable(GL_LINE_SMOOTH);
-#endif
-	glLineWidth(1.1f);
-	if (!g_Renderer.DoSkipSubmit())
-		glDrawArrays(GL_LINE_STRIP, 0, vertices.size() / 3);
-	glLineWidth(1.0f);
-#if !CONFIG2_GLES
-	glDisable(GL_LINE_SMOOTH);
-#endif
-}
-
 void CChart::DrawTriangleStrip(const CShaderProgramPtr& shader, const CGUIColor& color, const std::vector<float>& vertices) const
 {
 	shader->Uniform(str_color, color);
@@ -109,7 +92,7 @@ void CChart::DrawAxes(const CShaderProgramPtr& shader) const
 	DrawTriangleStrip(shader, m_AxisColor, vertices);
 }
 
-void CChart::Draw()
+void CChart::Draw(CCanvas2D& canvas)
 {
 	PROFILE3("render chart");
 
@@ -120,6 +103,32 @@ void CChart::Draw()
 	const float width = rect.GetWidth();
 	const float height = rect.GetHeight();
 
+	CVector2D scale(width / (m_RightTop.X - m_LeftBottom.X), height / (m_RightTop.Y - m_LeftBottom.Y));
+	std::vector<CVector2D> linePoints;
+	for (const CChartData& data : m_Series)
+	{
+		if (data.m_Points.empty())
+			continue;
+		
+		linePoints.clear();
+		for (const CVector2D& point : data.m_Points)
+		{
+			if (fabs(point.X) != std::numeric_limits<float>::infinity() && fabs(point.Y) != std::numeric_limits<float>::infinity())
+			{
+				linePoints.emplace_back(
+					rect.left + (point.X - m_LeftBottom.X) * scale.X,
+					rect.bottom - (point.Y - m_LeftBottom.Y) * scale.Y);
+			}
+			else
+			{
+				canvas.DrawLine(linePoints, 1.1f, data.m_Color);
+				linePoints.clear();
+			}
+		}
+		if (!linePoints.empty())
+			canvas.DrawLine(linePoints, 1.1f, data.m_Color);
+	}
+
 	// Setup the render state
 	CMatrix3D transform = GetDefaultGuiMatrix();
 	CShaderDefines lineDefines;
@@ -128,31 +137,6 @@ void CChart::Draw()
 	CShaderProgramPtr shader = tech->GetShader();
 	shader->Uniform(str_transform, transform);
 
-	CVector2D scale(width / (m_RightTop.X - m_LeftBottom.X), height / (m_RightTop.Y - m_LeftBottom.Y));
-	for (const CChartData& data : m_Series)
-	{
-		if (data.m_Points.empty())
-			continue;
-
-		std::vector<float> vertices;
-		for (const CVector2D& point : data.m_Points)
-		{
-			if (fabs(point.X) != std::numeric_limits<float>::infinity() && fabs(point.Y) != std::numeric_limits<float>::infinity())
-			{
-				vertices.push_back(rect.left + (point.X - m_LeftBottom.X) * scale.X);
-				vertices.push_back(rect.bottom - (point.Y - m_LeftBottom.Y) * scale.Y);
-				vertices.push_back(0.0f);
-			}
-			else
-			{
-				DrawLine(shader, data.m_Color, vertices);
-				vertices.clear();
-			}
-		}
-		if (!vertices.empty())
-			DrawLine(shader, data.m_Color, vertices);
-	}
-
 	if (m_AxisWidth > 0)
 		DrawAxes(shader);
 

source/gui/ObjectTypes/CChart.h

@@ -65,7 +65,7 @@ protected:
 	/**
 	 * Draws the Chart
 	 */
-	virtual void Draw();
+	virtual void Draw(CCanvas2D& canvas);
 
 	virtual CRect GetChartRect() const;
 

source/gui/ObjectTypes/CCheckBox.cpp

@@ -64,7 +64,7 @@ void CCheckBox::HandleMessage(SGUIMessage& Message)
 	}
 }
 
-void CCheckBox::Draw()
+void CCheckBox::Draw(CCanvas2D& UNUSED(canvas))
 {
 	m_pGUI.DrawSprite(
 		m_Checked ?

source/gui/ObjectTypes/CCheckBox.h

@@ -43,7 +43,7 @@ public:
 	/**
 	 * Draws the control
 	 */
-	virtual void Draw();
+	virtual void Draw(CCanvas2D& canvas);
 
 protected:
 	// Settings

source/gui/ObjectTypes/CDropDown.cpp

@@ -420,7 +420,7 @@ bool CDropDown::IsMouseOver() const
 		return m_CachedActualSize.PointInside(m_pGUI.GetMousePos());
 }
 
-void CDropDown::Draw()
+void CDropDown::Draw(CCanvas2D& UNUSED(canvas))
 {
 	const CGUISpriteInstance& sprite = m_Enabled ? m_Sprite : m_SpriteDisabled;
 	const CGUISpriteInstance& spriteOverlay = m_Enabled ? m_SpriteOverlay : m_SpriteOverlayDisabled;

source/gui/ObjectTypes/CDropDown.h

@@ -65,7 +65,7 @@ public:
 	/**
 	 * Draws the Button
 	 */
-	virtual void Draw();
+	virtual void Draw(CCanvas2D& canvas);
 
 	// This is one of the few classes we actually need to redefine this function
 	//  this is because the size of the control changes whether it is open

source/gui/ObjectTypes/CGUIDummyObject.h

@@ -35,7 +35,7 @@ class CGUIDummyObject : public IGUIObject
 public:
 	CGUIDummyObject(CGUI& pGUI) : IGUIObject(pGUI) {}
 
-	virtual void Draw() {}
+	virtual void Draw(CCanvas2D& UNUSED(canvas)) {}
 
 	/**
 	 * Empty can never be hovered. It is only a category.

source/gui/ObjectTypes/CHotkeyPicker.h

@@ -43,7 +43,7 @@ public:
 	virtual ~CHotkeyPicker();
 
 	// Do nothing.
-	virtual void Draw() {};
+	virtual void Draw(CCanvas2D& UNUSED(canvas)) {};
 
 	// Checks if the timer has passed and we need to fire a "combination" event.
 	virtual void Tick();

source/gui/ObjectTypes/CImage.cpp

@@ -31,7 +31,7 @@ CImage::~CImage()
 {
 }
 
-void CImage::Draw()
+void CImage::Draw(CCanvas2D& UNUSED(canvas))
 {
 	m_pGUI.DrawSprite(m_Sprite, m_CachedActualSize);
 }

source/gui/ObjectTypes/CImage.h

@@ -43,7 +43,7 @@ protected:
 	/**
 	 * Draws the Image
 	 */
-	virtual void Draw();
+	virtual void Draw(CCanvas2D& canvas);
 
 	CGUISimpleSetting<CGUISpriteInstance> m_Sprite;
 };

source/gui/ObjectTypes/CInput.cpp

@@ -1187,7 +1187,7 @@ void CInput::UpdateCachedSize()
 	m_GeneratedPlaceholderTextValid = false;
 }
 
-void CInput::Draw()
+void CInput::Draw(CCanvas2D& UNUSED(canvas))
 {
 	if (m_CursorBlinkRate > 0.0)
 	{

source/gui/ObjectTypes/CInput.h

@@ -95,7 +95,7 @@ protected:
 	/**
 	 * Draws the Text
 	 */
-	virtual void Draw();
+	virtual void Draw(CCanvas2D& canvas);
 
 	/**
 	 * Calculate m_CharacterPosition

source/gui/ObjectTypes/CList.cpp

@@ -299,7 +299,7 @@ InReaction CList::ManuallyHandleKeys(const SDL_Event_* ev)
 	return result;
 }
 
-void CList::Draw()
+void CList::Draw(CCanvas2D& UNUSED(canvas))
 {
 	DrawList(m_Selected, m_Sprite, m_SpriteOverlay, m_SpriteSelectArea, m_SpriteSelectAreaOverlay, m_TextColor);
 }

source/gui/ObjectTypes/CList.h

@@ -84,7 +84,7 @@ protected:
 	/**
 	 * Draws the List box
 	 */
-	virtual void Draw();
+	virtual void Draw(CCanvas2D& canvas);
 
 	virtual void CreateJSObject();
 

source/gui/ObjectTypes/CMiniMap.cpp

@@ -422,7 +422,7 @@ void CMiniMap::DrawTexture(CShaderProgramPtr shader, float coordMax, float angle
 //	most of the time, updating the framebuffer twice a frame.
 // Here it updates as ping-pong either texture or vertex array each sec to lower gpu stalling
 // (those operations cause a gpu sync, which slows down the way gpu works)
-void CMiniMap::Draw()
+void CMiniMap::Draw(CCanvas2D& UNUSED(canvas))
 {
 	PROFILE3("render minimap");
 

source/gui/ObjectTypes/CMiniMap.h

@@ -39,7 +39,7 @@ public:
 	static float GetShallowPassageHeight();
 
 protected:
-	virtual void Draw();
+	virtual void Draw(CCanvas2D& canvas);
 
 	/**
 	 * @see IGUIObject#HandleMessage()

source/gui/ObjectTypes/CProgressBar.cpp

@@ -53,7 +53,7 @@ void CProgressBar::HandleMessage(SGUIMessage& Message)
 	}
 }
 
-void CProgressBar::Draw()
+void CProgressBar::Draw(CCanvas2D& UNUSED(canvas))
 {
 	m_pGUI.DrawSprite(m_SpriteBackground, m_CachedActualSize);
 

source/gui/ObjectTypes/CProgressBar.h

@@ -36,7 +36,7 @@ protected:
 	/**
 	 * Draws the progress bar
 	 */
-	virtual void Draw();
+	virtual void Draw(CCanvas2D& canvas);
 
 	/**
 	 * @see IGUIObject#HandleMessage()

source/gui/ObjectTypes/CSlider.cpp

@@ -102,7 +102,7 @@ void CSlider::HandleMessage(SGUIMessage& Message)
 	}
 }
 
-void CSlider::Draw()
+void CSlider::Draw(CCanvas2D& UNUSED(canvas))
 {
 	CRect slider_line(m_CachedActualSize);
 	slider_line.left += m_ButtonSide / 2.0f;

source/gui/ObjectTypes/CSlider.h

@@ -44,7 +44,7 @@ protected:
 	 */
 	virtual void HandleMessage(SGUIMessage& Message);
 
-	virtual void Draw();
+	virtual void Draw(CCanvas2D& canvas);
 
 	/**
 	 * Change settings and send the script event

source/gui/ObjectTypes/CText.cpp

@@ -183,7 +183,7 @@ void CText::HandleMessage(SGUIMessage& Message)
 	IGUITextOwner::HandleMessage(Message);
 }
 
-void CText::Draw()
+void CText::Draw(CCanvas2D& UNUSED(canvas))
 {
 	m_pGUI.DrawSprite(m_Sprite, m_CachedActualSize);
 

source/gui/ObjectTypes/CText.h

@@ -65,7 +65,7 @@ protected:
 	/**
 	 * Draws the Text
 	 */
-	virtual void Draw();
+	virtual void Draw(CCanvas2D& canvas);
 
 	virtual void CreateJSObject();
 

source/gui/ObjectTypes/CTooltip.cpp

@@ -131,7 +131,7 @@ void CTooltip::HandleMessage(SGUIMessage& Message)
 	IGUITextOwner::HandleMessage(Message);
 }
 
-void CTooltip::Draw()
+void CTooltip::Draw(CCanvas2D& UNUSED(canvas))
 {
 	// Normally IGUITextOwner will handle this updating but since SetupText can modify the position
 	// we need to call it now *before* we do the rest of the drawing

source/gui/ObjectTypes/CTooltip.h

@@ -53,7 +53,7 @@ protected:
 	 */
 	virtual void HandleMessage(SGUIMessage& Message);
 
-	virtual void Draw();
+	virtual void Draw(CCanvas2D& canvas);
 
 	virtual float GetBufferedZ() const;