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Implemented support for explicit mipmap generation in sf::Texture and sf::RenderTexture. (#123)

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This commit is contained in:
binary1248 2015-09-23 17:05:39 +02:00
parent 2c7b58f406
commit 259811d59c
6 changed files with 168 additions and 24 deletions
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60
examples/opengl/OpenGL.cpp
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@ -44,26 +44,24 @@ int main()
if (!font.loadFromFile("resources/sansation.ttf"))
return EXIT_FAILURE;
sf::Text text("SFML / OpenGL demo", font);
sf::Text instructions("Press space to toggle sRGB conversion", font);
sf::Text sRgbInstructions("Press space to toggle sRGB conversion", font);
sf::Text mipmapInstructions("Press return to toggle mipmapping", font);
text.setFillColor(sf::Color(255, 255, 255, 170));
instructions.setFillColor(sf::Color(255, 255, 255, 170));
sRgbInstructions.setFillColor(sf::Color(255, 255, 255, 170));
mipmapInstructions.setFillColor(sf::Color(255, 255, 255, 170));
text.setPosition(250.f, 450.f);
instructions.setPosition(150.f, 500.f);
sRgbInstructions.setPosition(150.f, 500.f);
mipmapInstructions.setPosition(180.f, 550.f);
// Load an OpenGL texture.
// We could directly use a sf::Texture as an OpenGL texture (with its Bind() member function),
// but here we want more control on it (generate mipmaps, ...) so we create a new one from an image
GLuint texture = 0;
{
sf::Image image;
if (!image.loadFromFile("resources/texture.jpg"))
// Load a texture to apply to our 3D cube
sf::Texture texture;
if (!texture.loadFromFile("resources/texture.jpg"))
return EXIT_FAILURE;
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexImage2D(GL_TEXTURE_2D, 0, sRgb ? GL_SRGB8_ALPHA8 : GL_RGBA, image.getSize().x, image.getSize().y, 0, GL_RGBA, GL_UNSIGNED_BYTE, image.getPixelsPtr());
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
}
// Attempt to generate a mipmap for our cube texture
// We don't check the return value here since
// mipmapping is purely optional in this example
texture.generateMipmap();
// Enable Z-buffer read and write
glEnable(GL_DEPTH_TEST);
@ -84,7 +82,7 @@ int main()
// Bind the texture
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, texture);
sf::Texture::bind(&texture);
// Define a 3D cube (6 faces made of 2 triangles composed by 3 vertices)
static const GLfloat cube[] =
@ -146,6 +144,9 @@ int main()
// Create a clock for measuring the time elapsed
sf::Clock clock;
// Flag to track whether mipmapping is currently enabled
bool mipmapEnabled = true;
// Start game loop
while (window.isOpen())
{
@ -167,6 +168,25 @@ int main()
window.close();
}
// Return key: toggle mipmapping
if ((event.type == sf::Event::KeyPressed) && (event.key.code == sf::Keyboard::Return))
{
if (mipmapEnabled)
{
// We simply reload the texture to disable mipmapping
if (!texture.loadFromFile("resources/texture.jpg"))
return EXIT_FAILURE;
mipmapEnabled = false;
}
else
{
texture.generateMipmap();
mipmapEnabled = true;
}
}
// Space key: toggle sRGB conversion
if ((event.type == sf::Event::KeyPressed) && (event.key.code == sf::Keyboard::Space))
{
@ -205,15 +225,13 @@ int main()
// Draw some text on top of our OpenGL object
window.pushGLStates();
window.draw(text);
window.draw(instructions);
window.draw(sRgbInstructions);
window.draw(mipmapInstructions);
window.popGLStates();
// Finally, display the rendered frame on screen
window.display();
}
// Don't forget to destroy our texture
glDeleteTextures(1, &texture);
}
return EXIT_SUCCESS;

16
include/SFML/Graphics/RenderTexture.hpp
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@ -131,6 +131,22 @@ public:
////////////////////////////////////////////////////////////
bool isRepeated() const;
////////////////////////////////////////////////////////////
/// \brief Generate a mipmap using the current texture data
///
/// This function is similar to Texture::generateMipmap and operates
/// on the texture used as the target for drawing.
/// Be aware that any draw operation may modify the base level image data.
/// For this reason, calling this function only makes sense after all
/// drawing is completed and display has been called. Not calling display
/// after subsequent drawing will lead to undefined behavior if a mipmap
/// had been previously generated.
///
/// \return True if mipmap generation was successful, false if unsuccessful
///
////////////////////////////////////////////////////////////
bool generateMipmap();
////////////////////////////////////////////////////////////
/// \brief Activate or deactivate the render-texture for rendering
///

35
include/SFML/Graphics/Texture.hpp
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@ -445,6 +445,31 @@ public:
////////////////////////////////////////////////////////////
bool isRepeated() const;
////////////////////////////////////////////////////////////
/// \brief Generate a mipmap using the current texture data
///
/// Mipmaps are pre-computed chains of optimized textures. Each
/// level of texture in a mipmap is generated by halving each of
/// the previous level's dimensions. This is done until the final
/// level has the size of 1x1. The textures generated in this process may
/// make use of more advanced filters which might improve the visual quality
/// of textures when they are applied to objects much smaller than they are.
/// This is known as minification. Because fewer texels (texture elements)
/// have to be sampled from when heavily minified, usage of mipmaps
/// can also improve rendering performance in certain scenarios.
///
/// Mipmap generation relies on the necessary OpenGL extension being
/// available. If it is unavailable or generation fails due to another
/// reason, this function will return false. Mipmap data is only valid from
/// the time it is generated until the next time the base level image is
/// modified, at which point this function will have to be called again to
/// regenerate it.
///
/// \return True if mipmap generation was successful, false if unsuccessful
///
////////////////////////////////////////////////////////////
bool generateMipmap();
////////////////////////////////////////////////////////////
/// \brief Overload of assignment operator
///
@ -532,6 +557,15 @@ private:
////////////////////////////////////////////////////////////
static unsigned int getValidSize(unsigned int size);
////////////////////////////////////////////////////////////
/// \brief Invalidate the mipmap if one exists
///
/// This also resets the texture's minifying function.
/// This function is mainly for internal use by RenderTexture.
///
////////////////////////////////////////////////////////////
void invalidateMipmap();
////////////////////////////////////////////////////////////
// Member data
////////////////////////////////////////////////////////////
@ -543,6 +577,7 @@ private:
bool m_isRepeated; ///< Is the texture in repeat mode?
mutable bool m_pixelsFlipped; ///< To work around the inconsistency in Y orientation
bool m_fboAttachment; ///< Is this texture owned by a framebuffer object?
bool m_hasMipmap; ///< Has the mipmap been generated?
Uint64 m_cacheId; ///< Unique number that identifies the texture to the render target's cache
};

2
src/SFML/Graphics/GLExtensions.hpp
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@ -101,6 +101,7 @@
#define GLEXT_glCheckFramebufferStatus glCheckFramebufferStatusOES
#define GLEXT_glFramebufferTexture2D glFramebufferTexture2DOES
#define GLEXT_glFramebufferRenderbuffer glFramebufferRenderbufferOES
#define GLEXT_glGenerateMipmap glGenerateMipmapOES
#define GLEXT_GL_FRAMEBUFFER GL_FRAMEBUFFER_OES
#define GLEXT_GL_RENDERBUFFER GL_RENDERBUFFER_OES
#define GLEXT_GL_DEPTH_COMPONENT GL_DEPTH_COMPONENT16_OES
@ -228,6 +229,7 @@
#define GLEXT_glCheckFramebufferStatus glCheckFramebufferStatusEXT
#define GLEXT_glFramebufferTexture2D glFramebufferTexture2DEXT
#define GLEXT_glFramebufferRenderbuffer glFramebufferRenderbufferEXT
#define GLEXT_glGenerateMipmap glGenerateMipmapEXT
#define GLEXT_GL_FRAMEBUFFER GL_FRAMEBUFFER_EXT
#define GLEXT_GL_RENDERBUFFER GL_RENDERBUFFER_EXT
#define GLEXT_GL_COLOR_ATTACHMENT0 GL_COLOR_ATTACHMENT0_EXT

8
src/SFML/Graphics/RenderTexture.cpp
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@ -116,6 +116,13 @@ bool RenderTexture::isRepeated() const
}
////////////////////////////////////////////////////////////
bool RenderTexture::generateMipmap()
{
return m_texture.generateMipmap();
}
////////////////////////////////////////////////////////////
bool RenderTexture::setActive(bool active)
{
@ -131,6 +138,7 @@ void RenderTexture::display()
{
m_impl->updateTexture(m_texture.m_texture);
m_texture.m_pixelsFlipped = true;
m_texture.invalidateMipmap();
}
}

65
src/SFML/Graphics/Texture.cpp
View File

@ -88,6 +88,7 @@ m_sRgb (false),
m_isRepeated (false),
m_pixelsFlipped(false),
m_fboAttachment(false),
m_hasMipmap (false),
m_cacheId (getUniqueId())
{
}
@ -103,6 +104,7 @@ m_sRgb (copy.m_sRgb),
m_isRepeated (copy.m_isRepeated),
m_pixelsFlipped(false),
m_fboAttachment(false),
m_hasMipmap (false),
m_cacheId (getUniqueId())
{
if (copy.m_texture)
@ -217,6 +219,8 @@ bool Texture::create(unsigned int width, unsigned int height)
glCheck(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, m_isSmooth ? GL_LINEAR : GL_NEAREST));
m_cacheId = getUniqueId();
m_hasMipmap = false;
return true;
}
@ -298,6 +302,9 @@ bool Texture::loadFromImage(const Image& image, const IntRect& area)
pixels += 4 * width;
}
glCheck(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, m_isSmooth ? GL_LINEAR : GL_NEAREST));
m_hasMipmap = false;
// Force an OpenGL flush, so that the texture will appear updated
// in all contexts immediately (solves problems in multi-threaded apps)
glCheck(glFlush());
@ -425,6 +432,8 @@ void Texture::update(const Uint8* pixels, unsigned int width, unsigned int heigh
// Copy pixels from the given array to the texture
glCheck(glBindTexture(GL_TEXTURE_2D, m_texture));
glCheck(glTexSubImage2D(GL_TEXTURE_2D, 0, x, y, width, height, GL_RGBA, GL_UNSIGNED_BYTE, pixels));
glCheck(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, m_isSmooth ? GL_LINEAR : GL_NEAREST));
m_hasMipmap = false;
m_pixelsFlipped = false;
m_cacheId = getUniqueId();
}
@ -467,6 +476,8 @@ void Texture::update(const Window& window, unsigned int x, unsigned int y)
// Copy pixels from the back-buffer to the texture
glCheck(glBindTexture(GL_TEXTURE_2D, m_texture));
glCheck(glCopyTexSubImage2D(GL_TEXTURE_2D, 0, x, y, 0, 0, window.getSize().x, window.getSize().y));
glCheck(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, m_isSmooth ? GL_LINEAR : GL_NEAREST));
m_hasMipmap = false;
m_pixelsFlipped = true;
m_cacheId = getUniqueId();
}
@ -489,10 +500,18 @@ void Texture::setSmooth(bool smooth)
glCheck(glBindTexture(GL_TEXTURE_2D, m_texture));
glCheck(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, m_isSmooth ? GL_LINEAR : GL_NEAREST));
if (m_hasMipmap)
{
glCheck(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, m_isSmooth ? GL_LINEAR_MIPMAP_LINEAR : GL_NEAREST_MIPMAP_LINEAR));
}
else
{
glCheck(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, m_isSmooth ? GL_LINEAR : GL_NEAREST));
}
}
}
}
////////////////////////////////////////////////////////////
@ -561,6 +580,51 @@ bool Texture::isRepeated() const
}
////////////////////////////////////////////////////////////
bool Texture::generateMipmap()
{
if (!m_texture)
return false;
ensureGlContext();
// Make sure that extensions are initialized
priv::ensureExtensionsInit();
if (!GLEXT_framebuffer_object)
return false;
// Make sure that the current texture binding will be preserved
priv::TextureSaver save;
glCheck(glBindTexture(GL_TEXTURE_2D, m_texture));
glCheck(GLEXT_glGenerateMipmap(GL_TEXTURE_2D));
glCheck(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, m_isSmooth ? GL_LINEAR_MIPMAP_LINEAR : GL_NEAREST_MIPMAP_LINEAR));
m_hasMipmap = true;
return true;
}
////////////////////////////////////////////////////////////
void Texture::invalidateMipmap()
{
if (!m_hasMipmap)
return;
ensureGlContext();
// Make sure that the current texture binding will be preserved
priv::TextureSaver save;
glCheck(glBindTexture(GL_TEXTURE_2D, m_texture));
glCheck(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, m_isSmooth ? GL_LINEAR : GL_NEAREST));
m_hasMipmap = false;
}
////////////////////////////////////////////////////////////
void Texture::bind(const Texture* texture, CoordinateType coordinateType)
{
@ -641,6 +705,7 @@ Texture& Texture::operator =(const Texture& right)
std::swap(m_isRepeated, temp.m_isRepeated);
std::swap(m_pixelsFlipped, temp.m_pixelsFlipped);
std::swap(m_fboAttachment, temp.m_fboAttachment);
std::swap(m_hasMipmap, temp.m_hasMipmap);
m_cacheId = getUniqueId();
return *this;