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Tweak how the OpenGL 1.1 code behaves slightly; distortion with Windows 7's OpenGL emulation is now at most .1% instead of at most 2%.

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Originally committed to SVN as r3723.
This commit is contained in:
Thomas Goyne 2009-10-19 01:11:02 +00:00
parent 5b9da0c56a
commit 5404b45017
2 changed files with 77 additions and 47 deletions
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118
aegisub/src/video_out_gl.cpp
View file

@ -53,6 +53,7 @@
#include "utils.h"
#include "video_frame.h"
// Windows only has headers for OpenGL 1.1 and GL_CLAMP_TO_EDGE is 1.2
#ifndef GL_CLAMP_TO_EDGE
#define GL_CLAMP_TO_EDGE 0x812F
#endif
@ -66,12 +67,19 @@ namespace {
int dataOffset;
int sourceH;
int sourceW;
int textureH;
int textureW;
float destH;
float destW;
float destX;
float destY;
float texH;
float texW;
float texTop;
float texBottom;
float texLeft;
float texRight;
};
/// @brief Test if a texture can be created
/// @param width The width of the texture
@ -94,6 +102,7 @@ namespace {
VideoOutGL::VideoOutGL()
: maxTextureSize(0),
supportsRectangularTextures(false),
supportsGlClampToEdge(false),
internalFormat(0),
frameWidth(0),
frameHeight(0),
@ -102,10 +111,40 @@ VideoOutGL::VideoOutGL()
textureList(),
textureCount(0),
textureRows(0),
textureCols(0),
openGL11(false)
textureCols(0)
{ }
/// @brief Runtime detection of required OpenGL capabilities
void VideoOutGL::DetectOpenGLCapabilities() {
if (maxTextureSize != 0) return;
// Test for supported internalformats
if (TestTexture(64, 64, GL_RGBA8)) internalFormat = GL_RGBA8;
else if (TestTexture(64, 64, GL_RGBA)) internalFormat = GL_RGBA;
else throw VideoOutUnsupportedException(L"Could not create a 64x64 RGB texture in any format.");
// Test for the maximum supported texture size
glGetIntegerv(GL_MAX_TEXTURE_SIZE, &maxTextureSize);
while (maxTextureSize > 64 && !TestTexture(maxTextureSize, maxTextureSize, internalFormat)) maxTextureSize >>= 1;
wxLogDebug("VideoOutGL::DetectOpenGLCapabilities: Maximum texture size is %dx%d\n", maxTextureSize, maxTextureSize);
// Test for rectangular texture support
supportsRectangularTextures = TestTexture(maxTextureSize, maxTextureSize >> 1, internalFormat);
// Test GL_CLAMP_TO_EDGE support
GLuint texture;
glGenTextures(1, &texture);
glTexImage2D(GL_PROXY_TEXTURE_2D, 0, GL_RGBA8, 64, 64, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
if (glGetError()) {
supportsGlClampToEdge = false;
wxLogDebug("VideoOutGL::DetectOpenGLCapabilities: Using GL_CLAMP\n");
}
else {
supportsGlClampToEdge = true;
wxLogDebug("VideoOutGL::DetectOpenGLCapabilities: Using GL_CLAMP_TO_EDGE\n");
}
}
/// @brief If needed, create the grid of textures for displaying frames of the given format
/// @param width The frame's width
@ -117,25 +156,7 @@ void VideoOutGL::InitTextures(int width, int height, GLenum format, int bpp) {
if (width == frameWidth && height == frameHeight && format == frameFormat) return;
wxLogDebug("VideoOutGL::InitTextures: Video size: %dx%d\n", width, height);
// If nessesary, detect what the user's OpenGL supports
if (maxTextureSize == 0) {
// Test for supported internalformats
if (TestTexture(64, 64, GL_RGBA8)) internalFormat = GL_RGBA8;
else if (TestTexture(64, 64, GL_RGBA)) internalFormat = GL_RGBA;
else throw VideoOutUnsupportedException(L"Could not create a 64x64 RGB texture in any format.");
// Test for the maximum supported texture size
glGetIntegerv(GL_MAX_TEXTURE_SIZE, &maxTextureSize);
while (maxTextureSize > 64 && !TestTexture(maxTextureSize, maxTextureSize, internalFormat)) maxTextureSize >>= 1;
// Test for rectangular texture support
supportsRectangularTextures = TestTexture(maxTextureSize, maxTextureSize >> 1, internalFormat);
// Check OpenGL version
if (strncmp((const char *)glGetString(GL_VERSION), "1.1", 3) == 0) {
openGL11 = true;
}
}
DetectOpenGLCapabilities();
// Clean up old textures
if (textureIdList.size() > 0) {
@ -145,6 +166,7 @@ void VideoOutGL::InitTextures(int width, int height, GLenum format, int bpp) {
textureList.clear();
}
// Create the textures
textureRows = (int)ceil(double(height) / maxTextureSize);
textureCols = (int)ceil(double(width) / maxTextureSize);
textureIdList.resize(textureRows * textureCols);
@ -185,9 +207,20 @@ void VideoOutGL::InitTextures(int width, int height, GLenum format, int bpp) {
int w = textureW;
int h = textureH;
if (!supportsRectangularTextures) w = h = MAX(w, h);
if (supportsGlClampToEdge) {
ti.texLeft = 0.0f;
ti.texTop = 0.0f;
}
else {
// Stretch the texture a half pixel in each direction to eliminate the border
ti.texLeft = 1.0f / (2 * w);
ti.texTop = 1.0f / (2 * h);
}
// Calculate what percent of the texture is actually used
ti.texW = float(ti.sourceW) / w;
ti.texH = float(ti.sourceH) / h;
ti.texRight = float(ti.sourceW) / w - ti.texLeft;
ti.texBottom = float(ti.sourceH) / h - ti.texTop;
// destW/H is the percent of the output which this texture covers
ti.destW = float(w) / width;
@ -207,8 +240,7 @@ void VideoOutGL::InitTextures(int width, int height, GLenum format, int bpp) {
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glTexParameteri(GL_TEXTURE_MAG_FILTER)", err);
// GL_CLAMP_TO_EDGE was added in OpenGL 1.2, and W7's emulation only supports 1.1
GLint mode = openGL11 ? GL_REPEAT : GL_CLAMP_TO_EDGE;
GLint mode = supportsGlClampToEdge ? GL_CLAMP_TO_EDGE : GL_CLAMP;
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, mode);
if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glTexParameteri(GL_TEXTURE_WRAP_S)", err);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, mode);
@ -221,6 +253,7 @@ void VideoOutGL::InitTextures(int width, int height, GLenum format, int bpp) {
sourceY += sourceH;
}
// Store the information needed to know when the grid must be recreated
frameWidth = width;
frameHeight = height;
frameFormat = format;
@ -249,33 +282,28 @@ void VideoOutGL::DisplayFrame(AegiVideoFrame frame, int sw, int sh) {
glBindTexture(GL_TEXTURE_2D, ti.textureID);
if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glBindTexture", err);
glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, ti.sourceW, ti.sourceH, format, GL_UNSIGNED_BYTE, frame.data[0] + ti.dataOffset);
if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glTexSubImage2D", err);
glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glColor4f", err);
float top = 0.0f;
float bottom = ti.texH;
float left = 0.0f;
float right = 1.0f;
// Slightly stretch the texture under opengl 1.1 to make up for the lack of GL_CLAMP_TO_EDGE
if (openGL11) {
top = 0.01f;
bottom -= 0.01f;
left = 0.01f;
right -= 0.01f;
}
float top, bottom;
if (frame.flipped) {
float t = top;
top = bottom;
bottom = t;
top = ti.texBottom;
bottom = ti.texTop;
}
else {
top = ti.texTop;
bottom = ti.texBottom;
}
glBegin(GL_QUADS);
glTexCoord2f(left, top); glVertex2f(destX, destY);
glTexCoord2f(right, top); glVertex2f(destX + destW, destY);
glTexCoord2f(right, bottom); glVertex2f(destX + destW, destY + destH);
glTexCoord2f(left, bottom); glVertex2f(destX, destY + destH);
glTexCoord2f(ti.texLeft, top); glVertex2f(destX, destY);
glTexCoord2f(ti.texRight, top); glVertex2f(destX + destW, destY);
glTexCoord2f(ti.texRight, bottom); glVertex2f(destX + destW, destY + destH);
glTexCoord2f(ti.texLeft, bottom); glVertex2f(destX, destY + destH);
glEnd();
if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"GL_QUADS", err);
}

6
aegisub/src/video_out_gl.h
View file

@ -53,8 +53,11 @@ private:
int maxTextureSize;
/// Whether rectangular textures are supported by the user's graphics card
bool supportsRectangularTextures;
/// Whether GL_CLAMP_TO_EDGE is supported by the user's drivers
bool supportsGlClampToEdge;
/// The internalformat to use
int internalFormat;
/// The frame height which the texture grid has been set up for
int frameWidth;
/// The frame width which the texture grid has been set up for
@ -72,8 +75,7 @@ private:
/// The number of columns of textures
int textureCols;
bool openGL11;
void DetectOpenGLCapabilities();
void InitTextures(int width, int height, GLenum format, int bpp);
VideoOutGL(const VideoOutGL &);