GUIRenderer.cpp

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/* Copyright (C) 2013 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 "GUIRenderer.h"

#include "graphics/ShaderManager.h"
#include "graphics/TextureManager.h"
#include "gui/GUIutil.h"
#include "lib/ogl.h"
#include "lib/utf8.h"
#include "lib/res/h_mgr.h"
#include "lib/tex/tex.h"
#include "ps/CLogger.h"
#include "ps/Filesystem.h"
#include "renderer/Renderer.h"


using namespace GUIRenderer;


DrawCalls::DrawCalls()
{
}

// DrawCalls needs to be copyable, so it can be used in other copyable types.
// But actually copying data is hard, since we'd need to avoid losing track of
// who owns various pointers, so instead we just return an empty list.
// The list should get filled in again (by GUIRenderer::UpdateDrawCallCache)
// before it's used for rendering. (TODO: Is this class actually used safely
// in practice?)

DrawCalls::DrawCalls(const DrawCalls&)
    : std::vector<SDrawCall>()
{
}

DrawCalls& DrawCalls::operator=(const DrawCalls&)
{
    return *this;
}


void GUIRenderer::UpdateDrawCallCache(DrawCalls &Calls, const CStr& SpriteName, const CRect &Size, int CellID, std::map<CStr, CGUISprite> &Sprites)
{
    // This is called only when something has changed (like the size of the
    // sprite), so it doesn't need to be particularly efficient.

    // Clean up the old data
    Calls.clear();

    // If this object has zero size, there's nothing to render. (This happens
    // with e.g. tooltips that have zero size before they're first drawn, so
    // it isn't necessarily an error.)
    if (Size.left == Size.right && Size.top == Size.bottom)
        return;


    std::map<CStr, CGUISprite>::iterator it (Sprites.find(SpriteName));
    if (it == Sprites.end())
    {
        // Sprite not found. Check whether this a special sprite:
        //     "stretched:filename.ext" - stretched image
        //     "stretched:grayscale:filename.ext" - stretched grayscale image
        //     "cropped:(0.5, 0.25)"    - stretch this ratio (x,y) of the top left of the image
        //     "colour:r g b a"         - solid colour
        //
        // and if so, try to create it as a new sprite.
        if (SpriteName.substr(0, 10) == "stretched:")
        {
            // TODO: Should check (nicely) that this is a valid file?
            SGUIImage Image;
            
            // Allow grayscale images for disabled portraits
            if (SpriteName.substr(10, 10) == "grayscale:")
            {
                Image.m_TextureName = VfsPath("art/textures/ui") / wstring_from_utf8(SpriteName.substr(20));
                Image.m_Effects = new SGUIImageEffects;
                Image.m_Effects->m_Greyscale = true;
            }
            else
            {
                Image.m_TextureName = VfsPath("art/textures/ui") / wstring_from_utf8(SpriteName.substr(10));
            }

            CClientArea ca(CRect(0, 0, 0, 0), CRect(0, 0, 100, 100));
            Image.m_Size = ca;
            Image.m_TextureSize = ca;

            CGUISprite Sprite;
            Sprite.AddImage(Image);

            Sprites[SpriteName] = Sprite;
            
            it = Sprites.find(SpriteName);
            ENSURE(it != Sprites.end()); // The insertion above shouldn't fail
        }
        else if (SpriteName.substr(0, 8) == "cropped:")
        {
            // TODO: Should check (nicely) that this is a valid file?
            SGUIImage Image;

            double xRatio = SpriteName.BeforeFirst(",").AfterLast("(").ToDouble();
            double yRatio = SpriteName.BeforeFirst(")").AfterLast(",").ToDouble();
            
            int PathStart = SpriteName.Find(")") + 1;
            
            Image.m_TextureName = VfsPath("art/textures/ui") / wstring_from_utf8(SpriteName.substr(PathStart));

            CClientArea ca(CRect(0, 0, 0, 0), CRect(0, 0, 100, 100));
            CClientArea cb(CRect(0, 0, 0, 0), CRect(0, 0, 100/xRatio, 100/yRatio));
            Image.m_Size = ca;
            Image.m_TextureSize = cb;

            CGUISprite Sprite;
            Sprite.AddImage(Image);

            Sprites[SpriteName] = Sprite;
            
            it = Sprites.find(SpriteName);
            ENSURE(it != Sprites.end()); // The insertion above shouldn't fail
        }
        else if (SpriteName.substr(0, 7) == "colour:")
        {
            CStrW value = wstring_from_utf8(SpriteName.substr(7));
            CColor color;

            // Check colour is valid
            if (!GUI<CColor>::ParseString(value, color))
            {
                LOGERROR(L"GUI: Error parsing sprite 'colour' (\"%ls\")", value.c_str());
                return;
            }

            SGUIImage image;

            image.m_BackColor = color;

            CClientArea ca(CRect(0, 0, 0, 0), CRect(0, 0, 100, 100));
            image.m_Size = ca;
            image.m_TextureSize = ca;

            CGUISprite Sprite;
            Sprite.AddImage(image);

            Sprites[SpriteName] = Sprite;

            it = Sprites.find(SpriteName);
            ENSURE(it != Sprites.end()); // The insertion above shouldn't fail
        }
        else
        {
            // Otherwise, just complain and give up:
            LOGERROR(L"Trying to use a sprite that doesn't exist (\"%hs\").", SpriteName.c_str());
            return;
        }
    }

    Calls.reserve(it->second.m_Images.size());

    // Iterate through all the sprite's images, loading the texture and
    // calculating the texture coordinates
    std::vector<SGUIImage>::const_iterator cit;
    for (cit = it->second.m_Images.begin(); cit != it->second.m_Images.end(); ++cit)
    {
        SDrawCall Call(&*cit); // pointers are safe since we never modify sprites/images after startup

        CRect ObjectSize = cit->m_Size.GetClientArea(Size);

        if (ObjectSize.GetWidth() == 0.0 || ObjectSize.GetHeight() == 0.0)
        {
            // Zero sized object. Don't report as an error, since it's common for e.g. hitpoint bars.
            continue; // i.e. don't continue with this image
        }

        Call.m_Vertices = ObjectSize;
        if (cit->m_RoundCoordinates)
        {
            // Round the vertex coordinates to integers, to avoid ugly filtering artifacts
            Call.m_Vertices.left = (int)(Call.m_Vertices.left + 0.5f);
            Call.m_Vertices.right = (int)(Call.m_Vertices.right + 0.5f);
            Call.m_Vertices.top = (int)(Call.m_Vertices.top + 0.5f);
            Call.m_Vertices.bottom = (int)(Call.m_Vertices.bottom + 0.5f);
        }

        if (! cit->m_TextureName.empty())
        {
            CTextureProperties textureProps(cit->m_TextureName);
            textureProps.SetWrap(cit->m_WrapMode);
            CTexturePtr texture = g_Renderer.GetTextureManager().CreateTexture(textureProps);
            texture->Prefetch();
            Call.m_HasTexture = true;
            Call.m_Texture = texture;

            Call.m_EnableBlending = false; // will be overridden if the texture has an alpha channel

            Call.m_ObjectSize = ObjectSize;
            Call.m_CellID = CellID;
        }
        else
        {
            Call.m_HasTexture = false;
            // Enable blending if it's transparent (allowing a little error in the calculations)
            Call.m_EnableBlending = !(fabs(cit->m_BackColor.a - 1.0f) < 0.0000001f);
        }

        Call.m_BackColor = cit->m_BackColor;
        Call.m_BorderColor = cit->m_Border ? cit->m_BorderColor : CColor();
        Call.m_DeltaZ = cit->m_DeltaZ;

        if (!Call.m_HasTexture)
        {
            Call.m_Shader = g_Renderer.GetShaderManager().LoadEffect(str_gui_solid);
        }
        else if (cit->m_Effects)
        {
            if (cit->m_Effects->m_AddColor != CColor())
            {
                Call.m_Shader = g_Renderer.GetShaderManager().LoadEffect(str_gui_add);
                Call.m_ShaderColorParameter = cit->m_Effects->m_AddColor;
                // Always enable blending if something's being subtracted from
                // the alpha channel
                if (cit->m_Effects->m_AddColor.a < 0.f)
                    Call.m_EnableBlending = true;
            }
            else if (cit->m_Effects->m_Greyscale)
            {
                Call.m_Shader = g_Renderer.GetShaderManager().LoadEffect(str_gui_grayscale);
            }
            else /* Slight confusion - why no effects? */
            {
                Call.m_Shader = g_Renderer.GetShaderManager().LoadEffect(str_gui_basic);
            }
        }
        else
        {
            Call.m_Shader = g_Renderer.GetShaderManager().LoadEffect(str_gui_basic);
        }

        Calls.push_back(Call);
    }
}

CRect SDrawCall::ComputeTexCoords() const
{
    float TexWidth = m_Texture->GetWidth();
    float TexHeight = m_Texture->GetHeight();

    if (!TexWidth || !TexHeight)
    {
        return CRect(0, 0, 1, 1);
    }

    // Textures are positioned by defining a rectangular block of the
    // texture (usually the whole texture), and a rectangular block on
    // the screen. The texture is positioned to make those blocks line up.

    // Get the screen's position/size for the block
    CRect BlockScreen = m_Image->m_TextureSize.GetClientArea(m_ObjectSize);

    if (m_Image->m_FixedHAspectRatio)
        BlockScreen.right = BlockScreen.left + BlockScreen.GetHeight() * m_Image->m_FixedHAspectRatio;

    // Get the texture's position/size for the block:
    CRect BlockTex;

    // "real_texture_placement" overrides everything
    if (m_Image->m_TexturePlacementInFile != CRect())
    {
        BlockTex = m_Image->m_TexturePlacementInFile;
    }
    // Check whether this sprite has "cell_size" set (and non-zero)
    else if ((int)m_Image->m_CellSize.cx)
    {
        int cols = (int)TexWidth / (int)m_Image->m_CellSize.cx;
        if (cols == 0)
            cols = 1; // avoid divide-by-zero
        int col = m_CellID % cols;
        int row = m_CellID / cols;
        BlockTex = CRect(m_Image->m_CellSize.cx*col, m_Image->m_CellSize.cy*row,
                         m_Image->m_CellSize.cx*(col+1), m_Image->m_CellSize.cy*(row+1));
    }
    // Use the whole texture
    else
        BlockTex = CRect(0, 0, TexWidth, TexHeight);

    // When rendering, BlockTex will be transformed onto BlockScreen.
    // Also, TexCoords will be transformed onto ObjectSize (giving the
    // UV coords at each vertex of the object). We know everything
    // except for TexCoords, so calculate it:

    CPos translation (BlockTex.TopLeft()-BlockScreen.TopLeft());
    float ScaleW = BlockTex.GetWidth()/BlockScreen.GetWidth();
    float ScaleH = BlockTex.GetHeight()/BlockScreen.GetHeight();

    CRect TexCoords (
                // Resize (translating to/from the origin, so the
                // topleft corner stays in the same place)
                (m_ObjectSize-m_ObjectSize.TopLeft())
                .Scale(ScaleW, ScaleH)
                + m_ObjectSize.TopLeft()
                // Translate from BlockTex to BlockScreen
                + translation
    );

    // The tex coords need to be scaled so that (texwidth,texheight) is
    // mapped onto (1,1)
    TexCoords.left   /= TexWidth;
    TexCoords.right  /= TexWidth;
    TexCoords.top    /= TexHeight;
    TexCoords.bottom /= TexHeight;

    return TexCoords;
}

void GUIRenderer::Draw(DrawCalls &Calls, float Z)
{
    // Called every frame, to draw the object (based on cached calculations)

    // TODO: batching by shader/texture/etc would be nice

    CMatrix3D matrix = GetDefaultGuiMatrix();

    glDisable(GL_BLEND);

    // Set LOD bias so mipmapped textures are prettier
#if CONFIG2_GLES
#warning TODO: implement GUI LOD bias for GLES
#else
    glTexEnvf(GL_TEXTURE_FILTER_CONTROL, GL_TEXTURE_LOD_BIAS, -1.f);
#endif

    // Iterate through each DrawCall, and execute whatever drawing code is being called
    for (DrawCalls::const_iterator cit = Calls.begin(); cit != Calls.end(); ++cit)
    {
        cit->m_Shader->BeginPass();
        CShaderProgramPtr shader = cit->m_Shader->GetShader();
        shader->Uniform(str_transform, matrix);

        if (cit->m_HasTexture)
        {
            shader->Uniform(str_color, cit->m_ShaderColorParameter);
            shader->BindTexture(str_tex, cit->m_Texture);

            if (cit->m_EnableBlending || cit->m_Texture->HasAlpha()) // (shouldn't call HasAlpha before BindTexture)
            {
                glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
                glEnable(GL_BLEND);
            }

            CRect TexCoords = cit->ComputeTexCoords();

            // Ensure the quad has the correct winding order, and update texcoords to match
            CRect Verts = cit->m_Vertices;
            if (Verts.right < Verts.left)
            {
                std::swap(Verts.right, Verts.left);
                std::swap(TexCoords.right, TexCoords.left);
            }
            if (Verts.bottom < Verts.top)
            {
                std::swap(Verts.bottom, Verts.top);
                std::swap(TexCoords.bottom, TexCoords.top);
            }

            std::vector<float> data;
#define ADD(u, v, x, y, z) STMT(data.push_back(u); data.push_back(v); data.push_back(x); data.push_back(y); data.push_back(z))
            ADD(TexCoords.left, TexCoords.bottom, Verts.left, Verts.bottom, Z + cit->m_DeltaZ);
            ADD(TexCoords.right, TexCoords.bottom, Verts.right, Verts.bottom, Z + cit->m_DeltaZ);
            ADD(TexCoords.right, TexCoords.top, Verts.right, Verts.top, Z + cit->m_DeltaZ);

            ADD(TexCoords.right, TexCoords.top, Verts.right, Verts.top, Z + cit->m_DeltaZ);
            ADD(TexCoords.left, TexCoords.top, Verts.left, Verts.top, Z + cit->m_DeltaZ);
            ADD(TexCoords.left, TexCoords.bottom, Verts.left, Verts.bottom, Z + cit->m_DeltaZ);
#undef ADD

            shader->TexCoordPointer(GL_TEXTURE0, 2, GL_FLOAT, 5*sizeof(float), &data[0]);
            shader->VertexPointer(3, GL_FLOAT, 5*sizeof(float), &data[2]);
            glDrawArrays(GL_TRIANGLES, 0, 6);
        }
        else
        {
            shader->Uniform(str_color, cit->m_BackColor);

            if (cit->m_EnableBlending)
            {
                glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
                glEnable(GL_BLEND);
            }

            // Ensure the quad has the correct winding order
            CRect Verts = cit->m_Vertices;
            if (Verts.right < Verts.left)
                std::swap(Verts.right, Verts.left);
            if (Verts.bottom < Verts.top)
                std::swap(Verts.bottom, Verts.top);

            std::vector<float> data;
#define ADD(x, y, z) STMT(data.push_back(x); data.push_back(y); data.push_back(z))
            ADD(Verts.left, Verts.bottom, Z + cit->m_DeltaZ);
            ADD(Verts.right, Verts.bottom, Z + cit->m_DeltaZ);
            ADD(Verts.right, Verts.top, Z + cit->m_DeltaZ);

            ADD(Verts.right, Verts.top, Z + cit->m_DeltaZ);
            ADD(Verts.left, Verts.top, Z + cit->m_DeltaZ);
            ADD(Verts.left, Verts.bottom, Z + cit->m_DeltaZ);

            shader->VertexPointer(3, GL_FLOAT, 3*sizeof(float), &data[0]);
            glDrawArrays(GL_TRIANGLES, 0, 6);

            if (cit->m_BorderColor != CColor())
            {
                shader->Uniform(str_color, cit->m_BorderColor);

                data.clear();
                ADD(Verts.left + 0.5f, Verts.top + 0.5f, Z + cit->m_DeltaZ);
                ADD(Verts.right - 0.5f, Verts.top + 0.5f, Z + cit->m_DeltaZ);
                ADD(Verts.right - 0.5f, Verts.bottom - 0.5f, Z + cit->m_DeltaZ);
                ADD(Verts.left + 0.5f, Verts.bottom - 0.5f, Z + cit->m_DeltaZ);

                shader->VertexPointer(3, GL_FLOAT, 3*sizeof(float), &data[0]);
                glDrawArrays(GL_LINE_LOOP, 0, 4);
            }
#undef ADD
        }
        
        cit->m_Shader->EndPass();

        glDisable(GL_BLEND);
    }

#if CONFIG2_GLES
#warning TODO: implement GUI LOD bias for GLES
#else
    glTexEnvf(GL_TEXTURE_FILTER_CONTROL, GL_TEXTURE_LOD_BIAS, 0.f);
#endif
}