Unit CastleGLUtils

Check are any OpenGL errors recorded (in glGetError). If there are errors, our behavior depends on whether we were compiled with -dRELEASE. With -dRELEASE, we make WritelnWarning. This way eventual errors in release builds don't completely abort your program.

Note that the behavior on GL_OUT_OF_MEMORY is different. -dRELEASE does not matter here. Only GLOutOfMemoryError boolean dictates if we should raise an exception or merely make warning, regardless of -dRELEASE state.

Without -dRELEASE, we raise EOpenGLError. So a developer is strongly suggested to fix the code to not produce OpenGL errors, never ever.

Exceptions raised

EOpenGLError

Warning: this symbol is deprecated: this function is no longer useful, as you should not use GLU in cross-platform programs

Raise EOpenGLError for given OpenGL error code. This has calling convention suitable for registering this procedure as GLU_TESS_ERROR for gluTessCallback, or GLU_ERROR for gluQuadricCallback.

Comfortable wrappers for OpenGL glGet* that return a single value.

Guarantee that result is zero in case of OpenGL error. (Otherwise, OpenGL could leave them undefined and only set glGetError.)

Warning: this symbol is deprecated: use other methods to transform things, e.g. TCastleUserInterface position / anchors, or TCastleTransform for TCastleScene, or TTransformNode in X3D

Warning: this symbol is deprecated: use other methods to transform things, e.g. TCastleUserInterface position / anchors, or TCastleTransform for TCastleScene, or TTransformNode in X3D

Warning: this symbol is deprecated: use other methods to transform things, e.g. TCastleUserInterface position / anchors, or TCastleTransform for TCastleScene, or TTransformNode in X3D

Warning: this symbol is deprecated: use other methods to transform things, e.g. TCastleUserInterface position / anchors, or TCastleTransform for TCastleScene, or TTransformNode in X3D

Warning: this symbol is deprecated: use RenderContext.Viewport

Enable or disable given OpenGL flag.

Warning: this symbol is deprecated: use DrawPrimitive2D

Draw vertical line using OpenGL. Uses current OpenGL color.

Deprecated, do not draw lines directly like this, instead use DrawPrimitive2D or UI interface drawing like Theme.Draw and TDrawableImage.Draw.

Warning: this symbol is deprecated: use DrawPrimitive2D

Draw horizontal line using OpenGL. Uses current OpenGL color.

Deprecated, do not draw lines directly like this, instead use DrawPrimitive2D or UI interface drawing like Theme.Draw and TDrawableImage.Draw.

Warning: this symbol is deprecated: use DrawPrimitive2D to draw shapes

Draw arrow shape. Arrow is placed on Z = 0 plane, points to the up, has height = 2 (from y = 0 to y = 2) and width 1 (from x = -0.5 to 0.5).

Everything is drawn CCW when seen from standard view (x grows right, y up). Uses current OpenGL color.

Warning: this symbol is deprecated: use TCastleScene to draw 3D stuff

Draw axis (3 lines) around given position. Nothing is generated besides vertex positions — no normal vectors, no texture coords, nothing.

Warning: this symbol is deprecated: instead of this, use drawing routines that take Color from parameters or properties, like TCastleAbstractFont.Print(X,Y,Color,...) or TDrawableImage.Color

Call glColor, taking Opacity as separate Single argument. Deprecated, do not use colors like that, instead pass TCastleColor to appropriate routines like TCastleAbstractFont.Print.

Warning: this symbol is deprecated: instead of this, use drawing routines that take Color from parameters or properties, like TCastleAbstractFont.Print(X,Y,Color,...) or TDrawableImage.Color

Warning: this symbol is deprecated: do not use display lists; they are not available on OpenGLES and modern OpenGL

Call glGenLists(range) and checks the result.

Exceptions raised

EOpenGLNoMoreDisplayLists

When glGenLists(Range) returned zero for non-zero Range. The exception's Message shows Place, which may describe where this is called — makes it easier to debug.

Warning: this symbol is deprecated: do not use display lists; they are not available on OpenGLES and modern OpenGL

If List <> 0 then it does glDeleteList on List and sets List to 0. In other words this is simply glDeleteList but

1. only if List really should be deleted

2. sets List to 0 after deletion

If Buffer <> 0 then it does glDeleteBuffers and sets Buffer to 0.

Warning: this symbol is deprecated: set RenderContext.DepthBufferUpdate, RenderContext.ColorChannels explicitly, this allows to save/restore them reiably

Set color and depth buffers writeable or not.

This is just a shortcut for setting RenderContext.DepthBufferUpdate, RenderContext.ColorChannels.

Which are in turn shortcuts to doing this in OpenGL(ES):

glDepthMask(Writeable);
glColorMask(Writeable, Writeable, Writeable, Writeable);

Enable exactly one (or none, for Target=etNone) OpenGL texture target for fixed-function pipeline. Always use this instead of manually calling glDisable(GL_TEXTURE_2D), glEnable(GL_TEXTURE_2D) and such. This makes sure to have at most one texture target enabled, and disable others.

Remember that this state is different for every texture unit in OpenGL, in case you use multi-texturing.

Remember that not all texture targets are guaranteed to be supported by OpenGL. Target=etNone and Target=et2D are always supported. For the rest, check appropriate GLFeatures property (before even creating a texture with such type). If you pass an unsupported target type to this procedure, it will be ignored (all targets will be disabled, like for Target=etNone).

Note that this is only for fixed-function OpenGL pipeline. Shader pipeline completely ignores the enabled state of texture units.

PGLcharARBOrNil simply returns a Pointer(S), you can think of it as a NO-OP. If string is empty, this returns Nil, otherwise it works just like PGLcharARBOrNil(S): returns a Pointer(S) with appropriate type cast.

Initialize GLVersion and GLFeatures.

Draw a rectangle filled with a color.

Like with DrawPrimitive2D: Blending is automatically used if Color alpha < 1. ForceBlending forces the usage of blending. When it is False, we use blending only if Color[3] (alpha) < 1.

Draw a rectangle frame.

Like with DrawPrimitive2D: Blending is automatically used if Color alpha < 1. ForceBlending forces the usage of blending. When it is False, we use blending only if Color[3] (alpha) < 1.

Draw a circle. It may be scaled differently in X than Y, thus resembling an ellipse.

Like with DrawPrimitive2D: Blending is automatically used if Color alpha < 1. ForceBlending forces the usage of blending. When it is False, we use blending only if Color[3] (alpha) < 1.

Draw a circle outline. It may be scaled differently in X than Y, thus resembling an ellipse.

Like with DrawPrimitive2D: Blending is automatically used if Color alpha < 1. ForceBlending forces the usage of blending. When it is False, we use blending only if Color[3] (alpha) < 1.

Draw a simple 2D primitive with a given color. This can be used to draw a series of points, lines or triangles, depending on the Mode parameter.

Blending is automatically used if Color alpha < 1. ForceBlending forces the usage of blending. When it is False, we use blending only if Color[3] (alpha) < 1.

Parameters

LineWidth

Line width, only used when Mode indicates lines.

Note that values other than 1 are not guaranteed to be supported. While it's a fast method to have thick lines, it is implementation-limited in case of

1. desktop OpenGL with anti-aliasing, see https://www.opengl.org/sdk/docs/man/html/glLineWidth.xhtml

2. mobile OpenGLES, with or without anti-aliasing, see https://www.khronos.org/opengles/sdk/docs/man/xhtml/glLineWidth.xml

PointSize

Point size, only used when Mode indicates points.

Note that values other than 1 are not guaranteed to be supported. Mobile OpenGLES does not support setting point size like this. And desktop OpenGL limits point size in case anti-aliasing is used, see https://www.opengl.org/sdk/docs/man2/xhtml/glPointSize.xml .

Draw primitive, using a stipple (pattern) for line rendering. Note that the stipple is ignored on mobile (OpenGLES).

Draw a rectangle that modulates colors underneath, making nice animation to AFadeColor while FadeIntensity changes from 1.0 down to 0.0.

The GLFadeRectangleLight version makes a flash to AFadeColor, then goes back to normal. It works reasonably with any color (light or dark).

The GLFadeRectangleDark version makes additional flash to blackness in the middle (so it goes from no modulation, to AFadeColor, to pure black, and then back to normal). So the "Dark" version is a little more impressive when you're flashing with a dark color.

These are nice as a screen effect, to flash some color (e.g. flash red color when the player is hurt).

Only RGB portion of AFadeColor is used.

Warning: this symbol is deprecated: use GLFadeRectangleDark, or TCastleFlashEffect with Dark = true

Warning: this symbol is deprecated: use GLFadeRectangleDark, or TCastleFlashEffect with Dark = true

Warning: this symbol is deprecated: use DrawRectangle

Draw a rectangle with blending. Deprecated, use DrawRectangle instead.

Warning: this symbol is deprecated: use DrawRectangle

Call OpenGL glBlendFunc, https://registry.khronos.org/OpenGL-Refpages/gl4/html/glBlendFunc.xhtml . Accepts parameters as enumerated types TBlendingSourceFactor, TBlendingDestinationFactor. Secures from using source or destination factor unsupported on current OpenGL version: makes a warnings and falls back on a sensible default (so it will always call glBlendFunc anyway).

Multiline string describing attributes of current OpenGL(ES) library. This simply queries OpenGL(ES) using glGet* functions about many things. Does not change OpenGL(ES) state in any way.

Note that the last line of returned string does not terminate with a newline character (so e.g. you may want to do Writeln(GLInformationString) instead of just Write(GLInformationString)).

One-line string summarizing current OpenGL(ES).

Is GenerateMipmap avaiable. This checks some GL extensions/versions that give us glGenerateMipmap or glGenerateMipmapEXT call, used by GenerateMipmap.

Call glGenerateMipmap (or analogous function from some OpenGL extension).

Exceptions raised

EGenerateMipmapNotAvailable

If no glGenerateMipmap version is available on this OpenGL version. If you don't want to get this exception, you can always check HasGenerateMipmap before calling this.

Check the existence of OpenGL EXT_framebuffer_blit extension. See https://www.khronos.org/registry/OpenGL/extensions/EXT/EXT_framebuffer_blit.txt .

Warning: this symbol is deprecated: use TVector2

Warning: this symbol is deprecated: use PVector2

Warning: this symbol is deprecated: use TVector2Byte

Warning: this symbol is deprecated: use PVector2Byte

Warning: this symbol is deprecated: use TVector2Integer

Warning: this symbol is deprecated: use PVector2Integer

Warning: this symbol is deprecated: use TVector3

Warning: this symbol is deprecated: use PVector3

Warning: this symbol is deprecated: use TVector3Byte

Warning: this symbol is deprecated: use PVector3Byte

Warning: this symbol is deprecated: use TVector3Integer

Warning: this symbol is deprecated: use PVector3Integer

Warning: this symbol is deprecated: use TVector4

Warning: this symbol is deprecated: use PVector4

Warning: this symbol is deprecated: use TVector4Byte

Warning: this symbol is deprecated: use PVector4Byte

Warning: this symbol is deprecated: use TVector4Integer

Warning: this symbol is deprecated: use PVector4Integer

Warning: this symbol is deprecated: use TMatrix2

Warning: this symbol is deprecated: use PMatrix2

Warning: this symbol is deprecated: use TMatrix3

Warning: this symbol is deprecated: use PMatrix3

Warning: this symbol is deprecated: use TMatrix4

Warning: this symbol is deprecated: use PMatrix4

Values

• etNone
• et2D
• etCubeMap
• et3D

Part of CastleGLUtils unit: TGLFeatures and friends.

Values

• gsNone
• gsExtension
• gsStandard

Primitive to draw using DrawPrimitive2D. The modes correspond to OpenGL drawing modes, see https://www.opengl.org/wiki/Primitive https://www.opengl.org/sdk/docs/man2/xhtml/glBegin.xml

Values

• pmPoints
• pmLineStrip
• pmLineLoop
• pmLines
• pmTriangleStrip
• pmTriangleFan
• pmTriangles

Part of CastleGLUtils unit: EXT_framebuffer_blit constants and routines.

When GPU runs out of memory, raise exception (EOpenGLOutOfMemoryError) or merely make a warning. Merely making a warning is very risky (you risk all kinds of rendering artifacts), but sometimes the rendering is actually smooth even though GPU complains.

Warning: this symbol is deprecated: instead of this, use drawing routines that take Color from parameters or properties, like TCastleAbstractFont.Print(X,Y,Color,...) or TDrawableImage.Color

Current color, set by glColorv and used for TCastleAbstractFont font printing (in case you use deprecated TCastleAbstractFont.Print overloads without explicit colors).

Instead of this, use drawing routines that take Color from parameters or properties, like TCastleAbstractFont.Print(X,Y,Color,...) or TDrawableImage.Color.

Warning: this symbol is deprecated: use drawing routines that take position as parameters, like TDrawableImage.Draw(X,Y) or TCastleAbstractFont.Print(X,Y,...)

Global position for drawing 2D stuff. Do this use this. Instead of this, use drawing routines that take position as parameters, like TDrawableImage.Draw(X,Y) or TCastleAbstractFont.Print(X,Y,...).

Much more verbose logging of current context capabilities in GLInformationInitialize.