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Support reversed Z rendering and float32 offscreen depth buffer
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Combined, both options greatly improve camera depth accuracy compared to
OpenGL default Z mapping and int24 depth buffer.

Requires GL_ARB_clip_control and ARB_depth_buffer_float extensions
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@aftersomemath
aftersomemath committed Jun 22, 2023
1 parent 74747e2 commit c71a42c
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Showing 10 changed files with 193 additions and 17 deletions.
15 changes: 15 additions & 0 deletions include/mujoco/mjrender.h
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,15 @@ typedef enum mjtFramebuffer_ { // OpenGL framebuffer option
mjFB_OFFSCREEN // offscreen buffer
} mjtFramebuffer;

typedef enum mjtDepthMapping_ { // OpenGL depth buffer mapping (from znear to zfar)
mjDB_NEGONETOONE = 0, // Negative one to one (OpenGL default)
mjDB_ONETOZERO // Reversed Z buffer (decreases numerical error)
} mjtDepthMapping;

typedef enum mjtDepthPrecision_ { // OpenGL depth buffer precision
mjDB_INT24 = 0, // 24 bit integer buffer (OpenGL default)
mjDB_FLOAT32 // 32 bit float buffer
} mjtDepthPrecision;

typedef enum mjtFontScale_ { // font scale, used at context creation
mjFONTSCALE_50 = 50, // 50% scale, suitable for low-res rendering
Expand Down Expand Up @@ -151,6 +160,12 @@ struct mjrContext_ { // custom OpenGL context

// pixel output format
int readPixelFormat; // default color pixel format for mjr_readPixels

// depth buffer mode
int depthMapping; // depth buffer mapping from [znear zfar] to normalized device coordinates: mjDB_NEGONETOONE or mjDB_ONETOZERO

// depth buffer precision
int depthPrecision; // depth buffer precision: mjDB_INT24 or mjDB_FLOAT32
};
typedef struct mjrContext_ mjrContext;

Expand Down
18 changes: 18 additions & 0 deletions introspect/enums.py
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Original file line number Diff line number Diff line change
Expand Up @@ -609,6 +609,24 @@
('mjFB_OFFSCREEN', 1),
]),
)),
('mjtDepthMapping',
EnumDecl(
name='mjtDepthMapping',
declname='enum mjtDepthMapping_',
values=dict([
('mjDB_NEGONETOONE', 0),
('mjDB_ONETOZERO', 1),
]),
)),
('mjtDepthPrecision',
EnumDecl(
name='mjtDepthPrecision',
declname='enum mjtDepthPrecision_',
values=dict([
('mjDB_INT24', 0),
('mjDB_FLOAT32', 1),
]),
)),
('mjtFontScale',
EnumDecl(
name='mjtFontScale',
Expand Down
10 changes: 10 additions & 0 deletions introspect/structs.py
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Original file line number Diff line number Diff line change
Expand Up @@ -6735,6 +6735,16 @@
type=ValueType(name='int'),
doc='default color pixel format for mjr_readPixels',
),
StructFieldDecl(
name='depthMapping',
type=ValueType(name='int'),
doc='depth buffer mapping from [znear zfar] to normalized device coordinates: mjDB_NEGONETOONE or mjDB_ONETOZERO', # pylint: disable=line-too-long
),
StructFieldDecl(
name='depthPrecision',
type=ValueType(name='int'),
doc='depth buffer precision: mjDB_INT24 or mjDB_FLOAT32',
),
),
)),
('mjuiState',
Expand Down
34 changes: 34 additions & 0 deletions python/mujoco/render.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -34,6 +34,10 @@ class MjWrapper<raw::MjrContext> : public WrapperBase<raw::MjrContext> {
public:
MjWrapper();
MjWrapper(const MjModelWrapper& model, int fontscale);
MjWrapper(const MjModelWrapper& model,
int fontscale,
mjtDepthMapping depthmapping,
mjtDepthPrecision depthprecision);
MjWrapper(const MjWrapper&) = delete;
MjWrapper(MjWrapper&&) = default;
~MjWrapper() = default;
Expand Down Expand Up @@ -122,6 +126,35 @@ MjrContextWrapper::MjWrapper(const MjModelWrapper& model, int fontscale)
X_SKIN(skinfaceVBO),
X(charWidth),
X(charWidthBig) {}

MjrContextWrapper::MjWrapper(const MjModelWrapper& model,
int fontscale,
mjtDepthMapping depthmapping,
mjtDepthPrecision depthprecision)
: WrapperBase([fontscale, depthmapping, depthprecision](const raw::MjModel* m) {
raw::MjrContext *const ctx = new raw::MjrContext;
mjr_defaultContext(ctx);
ctx->depthMapping = depthmapping;
ctx->depthPrecision = depthprecision;
InterceptMjErrors(mjr_makeContext)(m, ctx, fontscale);
return ctx;
}(model.get()), &MjrContextCapsuleDestructor),
X(fogRGBA),
X(auxWidth),
X(auxHeight),
X(auxSamples),
X(auxFBO),
X(auxFBO_r),
X(auxColor),
X(auxColor_r),
X(textureType),
X(texture),
X_SKIN(skinvertVBO),
X_SKIN(skinnormalVBO),
X_SKIN(skintexcoordVBO),
X_SKIN(skinfaceVBO),
X(charWidth),
X(charWidthBig) {}
#undef X_SKIN
#undef X

Expand Down Expand Up @@ -166,6 +199,7 @@ PYBIND11_MODULE(_render, pymodule) {
py::class_<MjrContextWrapper> mjrContext(pymodule, "MjrContext");
mjrContext.def(py::init<>());
mjrContext.def(py::init<const MjModelWrapper&, int>());
mjrContext.def(py::init<const MjModelWrapper&, int, mjtDepthMapping, mjtDepthPrecision>());
mjrContext.def(
"free", [](MjrContextWrapper& self) { self.Free(); },
py::doc("Frees resources in current active OpenGL context, sets struct "
Expand Down
1 change: 1 addition & 0 deletions simulate/platform_ui_adapter.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@ PlatformUIAdapter::~PlatformUIAdapter() {

bool PlatformUIAdapter::RefreshMjrContext(const mjModel* m, int fontscale) {
if (m != last_model_ || fontscale != last_fontscale_) {
// con_.depthMapping = mjDB_ONETOZERO;
mjr_makeContext(m, &con_, fontscale);
last_model_ = m;
last_fontscale_ = fontscale;
Expand Down
18 changes: 15 additions & 3 deletions src/render/glad/glad.c
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Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,7 @@
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Based on the OpenGL loader generated by glad 0.1.35 on Mon Mar 21 12:42:33 2022.
// Based on the OpenGL loader generated by glad 0.1.34 on Thu Jun 22 14:40:03 2023.
//
// The original generated code is distributed under CC0.
// https://creativecommons.org/publicdomain/zero/1.0/
Expand All @@ -22,6 +22,8 @@
// APIs: gl=1.5
// Profile: compatibility
// Extensions:
// GL_ARB_clip_control,
// GL_ARB_depth_buffer_float,
// GL_ARB_framebuffer_object,
// GL_ARB_seamless_cube_map,
// GL_ARB_vertex_buffer_object,
Expand All @@ -32,9 +34,9 @@
// Reproducible: False
//
// Commandline:
// --profile="compatibility" --api="gl=1.5" --generator="c" --spec="gl" --extensions="GL_ARB_framebuffer_object,GL_ARB_seamless_cube_map,GL_ARB_vertex_buffer_object,GL_KHR_debug"
// --profile="compatibility" --api="gl=1.5" --generator="c" --spec="gl" --extensions="GL_ARB_clip_control,GL_ARB_depth_buffer_float,GL_ARB_framebuffer_object,GL_ARB_seamless_cube_map,GL_ARB_vertex_buffer_object,GL_KHR_debug"
// Online:
// https://glad.dav1d.de/#profile=compatibility&language=c&specification=gl&loader=on&api=gl%3D1.5&extensions=GL_ARB_framebuffer_object&extensions=GL_ARB_seamless_cube_map&extensions=GL_ARB_vertex_buffer_object&extensions=GL_KHR_debug
// https://glad.dav1d.de/#profile=compatibility&language=c&specification=gl&loader=on&api=gl%3D1.5&extensions=GL_ARB_clip_control&extensions=GL_ARB_depth_buffer_float&extensions=GL_ARB_framebuffer_object&extensions=GL_ARB_seamless_cube_map&extensions=GL_ARB_vertex_buffer_object&extensions=GL_KHR_debug

#if !defined(_WIN32) && !defined(__CYGWIN__) && !defined(__APPLE__) && \
!defined(__HAIKU__) && !defined(_GNU_SOURCE)
Expand Down Expand Up @@ -824,10 +826,13 @@ PFNGLWINDOWPOS3IPROC mjGlad_glWindowPos3i = NULL;
PFNGLWINDOWPOS3IVPROC mjGlad_glWindowPos3iv = NULL;
PFNGLWINDOWPOS3SPROC mjGlad_glWindowPos3s = NULL;
PFNGLWINDOWPOS3SVPROC mjGlad_glWindowPos3sv = NULL;
int mjGLAD_GL_ARB_clip_control = 0;
int mjGLAD_GL_ARB_depth_buffer_float = 0;
int mjGLAD_GL_ARB_framebuffer_object = 0;
int mjGLAD_GL_ARB_seamless_cube_map = 0;
int mjGLAD_GL_ARB_vertex_buffer_object = 0;
int mjGLAD_GL_KHR_debug = 0;
PFNGLCLIPCONTROLPROC mjGlad_glClipControl = NULL;
PFNGLISRENDERBUFFERPROC mjGlad_glIsRenderbuffer = NULL;
PFNGLBINDRENDERBUFFERPROC mjGlad_glBindRenderbuffer = NULL;
PFNGLDELETERENDERBUFFERSPROC mjGlad_glDeleteRenderbuffers = NULL;
Expand Down Expand Up @@ -1350,6 +1355,10 @@ static void mjGlad_load_GL_VERSION_1_5(GLADloadproc load) {
mjGlad_glGetBufferParameteriv = (PFNGLGETBUFFERPARAMETERIVPROC)load("glGetBufferParameteriv");
mjGlad_glGetBufferPointerv = (PFNGLGETBUFFERPOINTERVPROC)load("glGetBufferPointerv");
}
static void mjGlad_load_GL_ARB_clip_control(GLADloadproc load) {
if(!mjGLAD_GL_ARB_clip_control) return;
mjGlad_glClipControl = (PFNGLCLIPCONTROLPROC)load("glClipControl");
}
static void mjGlad_load_GL_ARB_framebuffer_object(GLADloadproc load) {
if(!mjGLAD_GL_ARB_framebuffer_object) return;
mjGlad_glIsRenderbuffer = (PFNGLISRENDERBUFFERPROC)load("glIsRenderbuffer");
Expand Down Expand Up @@ -1414,6 +1423,8 @@ static void mjGlad_load_GL_KHR_debug(GLADloadproc load) {
}
static int mjGlad_find_extensionsGL(void) {
if (!mjGlad_get_exts()) return 0;
mjGLAD_GL_ARB_clip_control = mjGlad_has_ext("GL_ARB_clip_control");
mjGLAD_GL_ARB_depth_buffer_float = mjGlad_has_ext("GL_ARB_depth_buffer_float");
mjGLAD_GL_ARB_framebuffer_object = mjGlad_has_ext("GL_ARB_framebuffer_object");
mjGLAD_GL_ARB_seamless_cube_map = mjGlad_has_ext("GL_ARB_seamless_cube_map");
mjGLAD_GL_ARB_vertex_buffer_object = mjGlad_has_ext("GL_ARB_vertex_buffer_object");
Expand Down Expand Up @@ -1486,6 +1497,7 @@ int mjGladLoadGLUnsafe() {
mjGlad_load_GL_VERSION_1_5(mjGlad_get_proc);

if (!mjGlad_find_extensionsGL()) return 0;
mjGlad_load_GL_ARB_clip_control(mjGlad_get_proc);
mjGlad_load_GL_ARB_framebuffer_object(mjGlad_get_proc);
mjGlad_load_GL_ARB_vertex_buffer_object(mjGlad_get_proc);
mjGlad_load_GL_KHR_debug(mjGlad_get_proc);
Expand Down
28 changes: 25 additions & 3 deletions src/render/glad/glad.h
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Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,7 @@
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Based on the OpenGL loader generated by glad 0.1.35 on Mon Mar 21 12:42:33 2022.
// Based on the OpenGL loader generated by glad 0.1.34 on Thu Jun 22 14:40:03 2023.
//
// The original generated code is distributed under CC0.
// https://creativecommons.org/publicdomain/zero/1.0/
Expand All @@ -22,6 +22,8 @@
// APIs: gl=1.5
// Profile: compatibility
// Extensions:
// GL_ARB_clip_control,
// GL_ARB_depth_buffer_float,
// GL_ARB_framebuffer_object,
// GL_ARB_seamless_cube_map,
// GL_ARB_vertex_buffer_object,
Expand All @@ -32,9 +34,9 @@
// Reproducible: False
//
// Commandline:
// --profile="compatibility" --api="gl=1.5" --generator="c" --spec="gl" --extensions="GL_ARB_framebuffer_object,GL_ARB_seamless_cube_map,GL_ARB_vertex_buffer_object,GL_KHR_debug"
// --profile="compatibility" --api="gl=1.5" --generator="c" --spec="gl" --extensions="GL_ARB_clip_control,GL_ARB_depth_buffer_float,GL_ARB_framebuffer_object,GL_ARB_seamless_cube_map,GL_ARB_vertex_buffer_object,GL_KHR_debug"
// Online:
// https://glad.dav1d.de/#profile=compatibility&language=c&specification=gl&loader=on&api=gl%3D1.5&extensions=GL_ARB_framebuffer_object&extensions=GL_ARB_seamless_cube_map&extensions=GL_ARB_vertex_buffer_object&extensions=GL_KHR_debug
// https://glad.dav1d.de/#profile=compatibility&language=c&specification=gl&loader=on&api=gl%3D1.5&extensions=GL_ARB_clip_control&extensions=GL_ARB_depth_buffer_float&extensions=GL_ARB_framebuffer_object&extensions=GL_ARB_seamless_cube_map&extensions=GL_ARB_vertex_buffer_object&extensions=GL_KHR_debug

#ifndef MUJOCO_SRC_RENDER_GLAD_GLAD_H_
#define MUJOCO_SRC_RENDER_GLAD_GLAD_H_
Expand Down Expand Up @@ -2304,6 +2306,15 @@ typedef void (APIENTRYP PFNGLGETBUFFERPOINTERVPROC)(GLenum target, GLenum pname,
GLAPI PFNGLGETBUFFERPOINTERVPROC mjGlad_glGetBufferPointerv;
#define glGetBufferPointerv mjGlad_glGetBufferPointerv
#endif
#define GL_LOWER_LEFT 0x8CA1
#define GL_UPPER_LEFT 0x8CA2
#define GL_NEGATIVE_ONE_TO_ONE 0x935E
#define GL_ZERO_TO_ONE 0x935F
#define GL_CLIP_ORIGIN 0x935C
#define GL_CLIP_DEPTH_MODE 0x935D
#define GL_DEPTH_COMPONENT32F 0x8CAC
#define GL_DEPTH32F_STENCIL8 0x8CAD
#define GL_FLOAT_32_UNSIGNED_INT_24_8_REV 0x8DAD
#define GL_INVALID_FRAMEBUFFER_OPERATION 0x0506
#define GL_FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING 0x8210
#define GL_FRAMEBUFFER_ATTACHMENT_COMPONENT_TYPE 0x8211
Expand Down Expand Up @@ -2487,6 +2498,17 @@ GLAPI PFNGLGETBUFFERPOINTERVPROC mjGlad_glGetBufferPointerv;
#define GL_STACK_OVERFLOW_KHR 0x0503
#define GL_STACK_UNDERFLOW_KHR 0x0504
#define GL_DISPLAY_LIST 0x82E7
#ifndef GL_ARB_clip_control
#define GL_ARB_clip_control 1
GLAPI int mjGLAD_GL_ARB_clip_control;
typedef void (APIENTRYP PFNGLCLIPCONTROLPROC)(GLenum origin, GLenum depth);
GLAPI PFNGLCLIPCONTROLPROC mjGlad_glClipControl;
#define glClipControl mjGlad_glClipControl
#endif
#ifndef GL_ARB_depth_buffer_float
#define GL_ARB_depth_buffer_float 1
GLAPI int mjGLAD_GL_ARB_depth_buffer_float;
#endif
#ifndef GL_ARB_framebuffer_object
#define GL_ARB_framebuffer_object 1
GLAPI int mjGLAD_GL_ARB_framebuffer_object;
Expand Down
36 changes: 28 additions & 8 deletions src/render/render_context.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1062,7 +1062,11 @@ static void makeShadow(const mjModel* m, mjrContext* con) {
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_R_TO_TEXTURE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC, GL_LEQUAL);
if (con->depthMapping == mjDB_ONETOZERO) {
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC, GL_GEQUAL);
} else {
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC, GL_LEQUAL);
}
glTexParameteri(GL_TEXTURE_2D, GL_DEPTH_TEXTURE_MODE, GL_INTENSITY);
glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR);
glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR);
Expand Down Expand Up @@ -1121,16 +1125,17 @@ static void makeOff(mjrContext* con) {
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, con->offColor);

// create depth and stencil buffer
GLenum depth_buffer_format = con->depthPrecision == mjDB_FLOAT32 ? GL_DEPTH32F_STENCIL8 : GL_DEPTH24_STENCIL8;
glGenRenderbuffers(1, &con->offDepthStencil);
if (!con->offDepthStencil) {
mju_error("Could not allocate offscreen depth and stencil buffer");
}
glBindRenderbuffer(GL_RENDERBUFFER, con->offDepthStencil);
if (con->offSamples) {
glRenderbufferStorageMultisample(GL_RENDERBUFFER, con->offSamples, GL_DEPTH24_STENCIL8,
glRenderbufferStorageMultisample(GL_RENDERBUFFER, con->offSamples, depth_buffer_format,
con->offWidth, con->offHeight);
} else {
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, con->offWidth, con->offHeight);
glRenderbufferStorage(GL_RENDERBUFFER, depth_buffer_format, con->offWidth, con->offHeight);
}
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT,
GL_RENDERBUFFER, con->offDepthStencil);
Expand Down Expand Up @@ -1169,7 +1174,7 @@ static void makeOff(mjrContext* con) {
mju_error("Could not allocate offscreen depth and stencil buffer_r");
}
glBindRenderbuffer(GL_RENDERBUFFER, con->offDepthStencil_r);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, con->offWidth, con->offHeight);
glRenderbufferStorage(GL_RENDERBUFFER, depth_buffer_format, con->offWidth, con->offHeight);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT,
GL_RENDERBUFFER, con->offDepthStencil_r);

Expand Down Expand Up @@ -1489,6 +1494,12 @@ void mjr_makeContext_offSize(const mjModel* m, mjrContext* con, int fontscale,
if (!mjGLAD_GL_ARB_vertex_buffer_object) {
mju_error("OpenGL ARB_vertex_buffer_object required");
}
if (!mjGLAD_GL_ARB_clip_control) {
mju_error("OpenGL ARB_clip_control required");
}
if (!mjGLAD_GL_ARB_depth_buffer_float) {
mju_error("OpenGL ARB_depth_buffer_float required");
}
con->glInitialized = 1;

// determine window availability (could be EGL-headless)
Expand Down Expand Up @@ -1535,8 +1546,15 @@ void mjr_makeContext_offSize(const mjModel* m, mjrContext* con, int fontscale,
glPixelStorei(GL_PACK_ALIGNMENT, 1);
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

// free previous context
// free previous context but keep depth settings
// Doing this is the only way users can control these
// settings without breaking changes to either the
// behaviour of mjr_makeContext or the signature
int oldDepthMapping = con->depthMapping;
int oldDepthPrecision = con->depthPrecision;
mjr_freeContext(con);
con->depthMapping = oldDepthMapping;
con->depthPrecision = oldDepthPrecision;

// no model: offscreen and font only
if (!m) {
Expand Down Expand Up @@ -1828,19 +1846,21 @@ MJAPI void mjr_resizeOffscreen(int width, int height, mjrContext* con) {
glRenderbufferStorage(GL_RENDERBUFFER, GL_RGBA8, con->offWidth, con->offHeight);
}


GLenum depth_buffer_format = con->depthPrecision == mjDB_FLOAT32 ? GL_DEPTH32F_STENCIL8 : GL_DEPTH24_STENCIL8;
glBindRenderbuffer(GL_RENDERBUFFER, con->offDepthStencil);
if (con->offSamples) {
glRenderbufferStorageMultisample(GL_RENDERBUFFER, con->offSamples, GL_DEPTH24_STENCIL8,
glRenderbufferStorageMultisample(GL_RENDERBUFFER, con->offSamples, depth_buffer_format,
con->offWidth, con->offHeight);
} else {
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, con->offWidth, con->offHeight);
glRenderbufferStorage(GL_RENDERBUFFER, depth_buffer_format, con->offWidth, con->offHeight);
}

if (con->offSamples) {
glBindRenderbuffer(GL_RENDERBUFFER, con->offColor_r);
glRenderbufferStorage(GL_RENDERBUFFER, GL_RGBA8, con->offWidth, con->offHeight);

glBindRenderbuffer(GL_RENDERBUFFER, con->offDepthStencil_r);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, con->offWidth, con->offHeight);
glRenderbufferStorage(GL_RENDERBUFFER, depth_buffer_format, con->offWidth, con->offHeight);
}
}
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