Allow using single color channel for font texture

src/font/font_with_face.cpp

@@ -22,6 +22,7 @@
 #include "font/font_manager.hpp"
 #include "font/font_settings.hpp"
 #include "graphics/2dutils.hpp"
+#include "graphics/central_settings.hpp"
 #include "graphics/irr_driver.hpp"
 #include "graphics/stk_texture.hpp"
 #include "graphics/stk_tex_manager.hpp"
@@ -131,13 +132,24 @@ void FontWithFace::loadGlyphInfo(wchar_t c)
  */
 void FontWithFace::createNewGlyphPage()
 {
-    uint8_t* data = new uint8_t[getGlyphPageSize() * getGlyphPageSize() * 4]();
+#ifndef SERVER_ONLY
+    uint8_t* data = new uint8_t[getGlyphPageSize() * getGlyphPageSize() *
+    (CVS->isARBTextureSwizzleUsable() ? 1 : 4)];
+#else
+    uint8_t* data = NULL;
+#endif
     m_current_height = 0;
     m_used_width = 0;
     m_used_height = 0;
     STKTexture* stkt = new STKTexture(data, typeid(*this).name() +
         StringUtils::toString(m_spritebank->getTextureCount()),
-        getGlyphPageSize());
+        getGlyphPageSize(),
+#ifndef SERVER_ONLY
+        CVS->isARBTextureSwizzleUsable()
+#else
+        false
+#endif
+        );
     m_spritebank->addTexture(stkt);
     STKTexManager::getInstance()->addTexture(stkt);
 }   // createNewGlyphPage
@@ -180,6 +192,25 @@ void FontWithFace::insertGlyph(wchar_t c, const GlyphInfo& gi)
         createNewGlyphPage();
     }
 
+    // Determine the linebreak location
+    if (m_used_width + texture_size.Width > getGlyphPageSize())
+    {
+        m_used_width  = 0;
+        m_used_height += m_current_height;
+        m_current_height = 0;
+    }
+
+    const unsigned int cur_tex = m_spritebank->getTextureCount() -1;
+#ifndef SERVER_ONLY
+    video::ITexture* tex = m_spritebank->getTexture(cur_tex);
+    glBindTexture(GL_TEXTURE_2D, tex->getOpenGLTextureName());
+    if (CVS->isARBTextureSwizzleUsable())
+    {
+        glTexSubImage2D(GL_TEXTURE_2D, 0, m_used_width, m_used_height,
+            bits.width, bits.rows, GL_RED, GL_UNSIGNED_BYTE, bits.buffer);
+    }
+    else
+    {
         std::vector<uint32_t> image_data;
         image_data.resize(texture_size.Width * texture_size.Height,
             video::SColor(0, 255, 255, 255).color);
@@ -208,33 +239,10 @@ void FontWithFace::insertGlyph(wchar_t c, const GlyphInfo& gi)
             default:
                 assert(false);
         }
-
-    // Done creating a single glyph, now copy to the glyph page...
-    // Determine the linebreak location
-    if (m_used_width + texture_size.Width > getGlyphPageSize())
-    {
-        m_used_width  = 0;
-        m_used_height += m_current_height;
-        m_current_height = 0;
-    }
-
-    const unsigned int cur_tex = m_spritebank->getTextureCount() -1;
-#ifndef SERVER_ONLY
-    video::ITexture* tex = m_spritebank->getTexture(cur_tex);
-    glBindTexture(GL_TEXTURE_2D, tex->getOpenGLTextureName());
-    unsigned int format = GL_BGRA;
-#if defined(USE_GLES2)
-    if (!CVS->isEXTTextureFormatBGRA8888Usable())
-        format = GL_RGBA;
-#endif
         glTexSubImage2D(GL_TEXTURE_2D, 0, m_used_width, m_used_height,
-        texture_size.Width, texture_size.Height, format, GL_UNSIGNED_BYTE,
+            texture_size.Width, texture_size.Height, GL_BGRA, GL_UNSIGNED_BYTE,
             image_data.data());
-    //glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+    }
-    //static GLint swizzle_mask[] = { GL_ONE, GL_ONE, GL_ONE, GL_RED };
-    //glTexParameteriv(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_RGBA, swizzle_mask);
-    //glTexSubImage2D(GL_TEXTURE_2D, 0, m_used_width, m_used_height, bits.width, bits.rows, GL_RED, GL_UNSIGNED_BYTE, bits.buffer);
-    //glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
     if (tex->hasMipMaps())
         glGenerateMipmap(GL_TEXTURE_2D);
     glBindTexture(GL_TEXTURE_2D, 0);

src/graphics/central_settings.cpp

@@ -51,6 +51,7 @@ void CentralVideoSettings::init()
     hasExplicitAttribLocation = false;
     hasGS = false;
     hasTextureFilterAnisotropic = false;
+    hasTextureSwizzle = false;
 
 #if defined(USE_GLES2)
     hasBGRA = false;
@@ -182,7 +183,11 @@ void CentralVideoSettings::init()
             hasGS = true;
             Log::info("GLDriver", "Geometry Shaders Present");
         }
-
+        if (hasGLExtension("GL_ARB_texture_swizzle"))
+        {
+            hasTextureSwizzle = true;
+            Log::info("GLDriver", "ARB Texture Swizzle Present");
+        }
         // Only unset the high def textures if they are set as default. If the
         // user has enabled them (bit 1 set), then leave them enabled.
         if (GraphicsRestrictions::isDisabled(GraphicsRestrictions::GR_HIGHDEFINITION_TEXTURES) &&
@@ -228,6 +233,7 @@ void CentralVideoSettings::init()
         if (m_glsl == true)
         {
             hasTextureStorage = true;
+            hasTextureSwizzle = true;
         }
 
         if (!GraphicsRestrictions::isDisabled(GraphicsRestrictions::GR_TEXTURE_FORMAT_BGRA8888) &&
@@ -447,4 +453,10 @@ bool CentralVideoSettings::supportsHardwareSkinning() const
 {
     return isARBUniformBufferObjectUsable();
 }
+
+bool CentralVideoSettings::isARBTextureSwizzleUsable() const
+{
+    return m_glsl && hasTextureSwizzle;
+}
+
 #endif   // !SERVER_ONLY

src/graphics/central_settings.hpp

@@ -43,6 +43,7 @@ private:
     bool hasImageLoadStore;
     bool hasMultiDrawIndirect;
     bool hasTextureFilterAnisotropic;
+    bool hasTextureSwizzle;
 
 #if defined(USE_GLES2)
     bool hasBGRA;
@@ -82,6 +83,7 @@ public:
     bool isARBMultiDrawIndirectUsable() const;
     bool isARBExplicitAttribLocationUsable() const;
     bool isEXTTextureFilterAnisotropicUsable() const;
+    bool isARBTextureSwizzleUsable() const;
 
 #if defined(USE_GLES2)
     bool isEXTTextureFormatBGRA8888Usable() const;

src/graphics/stk_texture.cpp

@@ -82,6 +82,8 @@ void STKTexture::reload(bool no_upload, uint8_t* preload_data,
     if (ProfileWorld::isNoGraphics())
     {
         m_texture_name = 1;
+        if (preload_data)
+            delete[] preload_data;
         return;
     }
 #ifndef SERVER_ONLY
@@ -156,8 +158,8 @@ void STKTexture::reload(bool no_upload, uint8_t* preload_data,
 
     const unsigned int w = m_size.Width;
     const unsigned int h = m_size.Height;
-    unsigned int format = GL_BGRA;
+    unsigned int format = single_channel ? GL_RED : GL_BGRA;
-    unsigned int internal_format = GL_RGBA;
+    unsigned int internal_format = single_channel ? GL_RED : GL_RGBA;
 
 #if !defined(USE_GLES2)
     if (m_mesh_texture && CVS->isTextureCompressionEnabled())
@@ -166,14 +168,14 @@ void STKTexture::reload(bool no_upload, uint8_t* preload_data,
             GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT :
             GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
     }
-    else
+    else if (!single_channel)
     {
         internal_format = m_srgb ? GL_SRGB_ALPHA : GL_RGBA;
     }
 #endif
 
 #if defined(USE_GLES2)
-    if (!CVS->isEXTTextureFormatBGRA8888Usable())
+    if (!CVS->isEXTTextureFormatBGRA8888Usable() && !single_channel)
     {
         format = GL_RGBA;
         for (unsigned int i = 0; i < w * h; i++)
@@ -206,6 +208,14 @@ void STKTexture::reload(bool no_upload, uint8_t* preload_data,
         glBindTexture(GL_TEXTURE_2D, m_texture_name);
         if (!reload)
         {
+            if (single_channel)
+            {
+                glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_R, GL_ONE);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_G, GL_ONE);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_B, GL_ONE);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_A, GL_RED);
+            }
             glTexImage2D(GL_TEXTURE_2D, 0, internal_format, w, h, 0, format,
                 GL_UNSIGNED_BYTE, data);
         }
@@ -220,7 +230,7 @@ void STKTexture::reload(bool no_upload, uint8_t* preload_data,
             glGenerateMipmap(GL_TEXTURE_2D);
     }
 
-    m_texture_size = w * h * 4 /*BRGA*/;
+    m_texture_size = w * h * (single_channel ? 1 : 4);
     if (no_upload)
         m_texture_image = orig_img;
     else if (orig_img)
@@ -454,10 +464,10 @@ bool STKTexture::hasMipMaps() const
 //-----------------------------------------------------------------------------
 void* STKTexture::lock(video::E_TEXTURE_LOCK_MODE mode, u32 mipmap_level)
 {
-#ifndef SERVER_ONLY
     if (m_texture_image)
         return m_texture_image->lock();
 
+#if !(defined(SERVER_ONLY) || defined(USE_GLES2))
     uint8_t* pixels = new uint8_t[m_size.Width * m_size.Height * 4]();
     GLint tmp_texture;
     glGetIntegerv(GL_TEXTURE_BINDING_2D, &tmp_texture);