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Updates from Frederic to use 2 texture units and a color blend function rather than 3 texture units.

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This commit is contained in:
ehofman
2004-05-21 14:50:49 +00:00
parent b199f733f7
commit 0f5f30b993
2 changed files with 42 additions and 13 deletions
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36
simgear/scene/sky/cloud.cxx
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@@ -54,6 +54,7 @@ static GLuint normalization_cube_map;
static glActiveTextureProc glActiveTexturePtr = 0;
static glClientActiveTextureProc glClientActiveTexturePtr = 0;
static glBlendColorProc glBlendColorPtr = 0;
bool SGCloudLayer::enable_bump_mapping = false;
@@ -307,13 +308,15 @@ SGCloudLayer::rebuild()
bump_mapping = SGIsOpenGLExtensionSupported("GL_ARB_multitexture") &&
SGIsOpenGLExtensionSupported("GL_ARB_texture_cube_map") &&
SGIsOpenGLExtensionSupported("GL_ARB_texture_env_combine") &&
SGIsOpenGLExtensionSupported("GL_ARB_texture_env_dot3") && true;
SGIsOpenGLExtensionSupported("GL_ARB_texture_env_dot3") &&
SGIsOpenGLExtensionSupported("GL_ARB_imaging");
if ( bump_mapping ) {
glGetIntegerv( GL_MAX_TEXTURE_UNITS_ARB, &nb_texture_unit );
if ( nb_texture_unit < 2 ) {
bump_mapping = false;
}
nb_texture_unit = 2; // Force the number of units for now
}
if ( bump_mapping ) {
@@ -329,6 +332,7 @@ SGCloudLayer::rebuild()
glActiveTexturePtr = (glActiveTextureProc)SGLookupFunction("glActiveTextureARB");
glClientActiveTexturePtr = (glClientActiveTextureProc)SGLookupFunction("glClientActiveTextureARB");
glBlendColorPtr = (glBlendColorProc)SGLookupFunction("glBlendColor");
cloud_path.set(texture_path.str());
cloud_path.append("overcast.rgb");
@@ -850,8 +854,10 @@ void SGCloudLayer::draw( bool top ) {
glDisable( GL_LIGHTING );
glDisable( GL_CULL_FACE );
glEnable( GL_ALPHA_TEST );
glAlphaFunc ( GL_GREATER, 0.1 ) ;
if ( layer_coverage == SG_CLOUD_FEW ) {
glEnable( GL_ALPHA_TEST );
glAlphaFunc ( GL_GREATER, 0.01 );
}
glEnable( GL_BLEND );
glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
@@ -909,6 +915,8 @@ void SGCloudLayer::draw( bool top ) {
glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_DOT3_RGB_ARB );
glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB );
glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_PREVIOUS_ARB );
glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_REPLACE );
if ( nb_texture_unit >= 3 ) {
glActiveTexturePtr( GL_TEXTURE2_ARB );
@@ -956,6 +964,9 @@ void SGCloudLayer::draw( bool top ) {
glClientActiveTexturePtr( GL_TEXTURE0_ARB );
glDisableClientState( GL_COLOR_ARRAY );
glEnable( GL_LIGHTING );
glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
} else {
glClientActiveTexturePtr( GL_TEXTURE0_ARB );
@@ -967,7 +978,6 @@ void SGCloudLayer::draw( bool top ) {
glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
//Disable textures
glDisable( GL_TEXTURE_2D );
@@ -987,8 +997,17 @@ void SGCloudLayer::draw( bool top ) {
glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
glDepthFunc(GL_LEQUAL);
//Enable multiplicative blending
glBlendFunc( GL_DST_COLOR, GL_ZERO );
glEnable( GL_LIGHTING );
sgVec4 color;
ssgGetLight( 0 )->getColour( GL_DIFFUSE, color );
float average = ( color[0] + color[1] + color[2] ) / 3.0f;
sgVec4 averageColor;
sgSetVec4( averageColor, average, average, average, 1.0f );
ssgGetLight( 0 )->setColour( GL_DIFFUSE, averageColor );
glBlendColorPtr( average, average, average, 1.0f );
glBlendFunc( GL_ONE_MINUS_CONSTANT_COLOR, GL_CONSTANT_COLOR );
//Perform a second pass to color the torus
//Bind decal texture
@@ -1014,6 +1033,8 @@ void SGCloudLayer::draw( bool top ) {
glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
ssgGetLight( 0 )->setColour( GL_DIFFUSE, color );
glDisableClientState( GL_TEXTURE_COORD_ARRAY );
}
//Disable texture
@@ -1022,10 +1043,7 @@ void SGCloudLayer::draw( bool top ) {
glDisableClientState( GL_VERTEX_ARRAY );
glDisableClientState( GL_NORMAL_ARRAY );
glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
glEnable( GL_LIGHTING );
glEnable( GL_CULL_FACE );
glDepthFunc(GL_LESS);

19
simgear/screen/extensions.hxx
View File

@@ -82,13 +82,24 @@ inline void (*SGLookupFunction(const char *func))()
* OpenGL 1.2 and 1.3 enumerants
*/
#ifndef GL_CLAMP_TO_EDGE
#ifndef GL_VERSION_1_2
#define GL_CLAMP_TO_EDGE 0x812F
#define GL_TEXTURE_WRAP_R 0x8072
#define GL_BLEND_EQUATION 0x8009
#define GL_MIN 0x8007
#define GL_MAX 0x8008
#define GL_FUNC_ADD 0x8006
#define GL_FUNC_SUBTRACT 0x800A
#define GL_FUNC_REVERSE_SUBTRACT 0x800B
#define GL_BLEND_COLOR 0x8005
#define GL_CONSTANT_COLOR 0x8001
#define GL_ONE_MINUS_CONSTANT_COLOR 0x8002
#define GL_CONSTANT_ALPHA 0x8003
#define GL_ONE_MINUS_CONSTANT_ALPHA 0x8004
#endif
#ifndef GL_TEXTURE_WRAP_R
#define GL_TEXTURE_WRAP_R 0x8072
#endif
typedef void (APIENTRY * glBlendEquationProc) (GLenum mode );
typedef void (APIENTRY * glBlendColorProc) (GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha );
/* OpenGL extension declarations */