Support reversed Z rendering and float32 offscreen depth buffer

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

include/mujoco/mjrender.h

@@ -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
@@ -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;
 

introspect/enums.py

@@ -621,6 +621,24 @@ ENUMS: Mapping[str, EnumDecl] = dict([
              ('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',

introspect/structs.py

@@ -7126,6 +7126,16 @@ STRUCTS: Mapping[str, StructDecl] = dict([
                  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',

python/mujoco/render.cc

@@ -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;
@@ -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
 
@@ -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 "

simulate/platform_ui_adapter.cc

@@ -27,6 +27,7 @@ void PlatformUIAdapter::FreeMjrContext() {
 
 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;

src/render/glad/glad.c

@@ -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/
@@ -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,
@@ -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(__GNUC__) && !defined(__clang__)
 #pragma GCC diagnostic push
@@ -829,10 +831,13 @@ 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;
@@ -1355,6 +1360,10 @@ 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");
@@ -1419,6 +1428,8 @@ 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");
@@ -1491,6 +1502,7 @@ int mjGladLoadGLUnsafe(void) {
     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);

src/render/glad/glad.h

@@ -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/
@@ -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,
@@ -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_
@@ -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
@@ -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;

src/render/render_context.c

@@ -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);
@@ -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);
@@ -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);
 
@@ -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)
@@ -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) {
@@ -1828,12 +1846,14 @@ 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) {
@@ -1841,6 +1861,6 @@ MJAPI void mjr_resizeOffscreen(int width, int height, mjrContext* con) {
     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);
   }
 }

src/render/render_gl3.c

@@ -498,6 +498,11 @@ static void initGL3(const mjvScene* scn, const mjrContext* con) {
   // common options
   glDisable(GL_BLEND);
   glEnable(GL_NORMALIZE);
+  if (con->depthMapping == mjDB_ONETOZERO) {
+    glClipControl(GL_LOWER_LEFT, GL_ZERO_TO_ONE);
+  } else {
+    glClipControl(GL_LOWER_LEFT, GL_NEGATIVE_ONE_TO_ONE);
+  }
   glEnable(GL_DEPTH_TEST);
   glDepthMask(GL_TRUE);
   if (scn->flags[mjRND_CULL_FACE]) {
@@ -506,11 +511,19 @@ static void initGL3(const mjvScene* scn, const mjrContext* con) {
     glDisable(GL_CULL_FACE);
   }
   glShadeModel(GL_SMOOTH);
-  glDepthFunc(GL_LEQUAL);
+  if (con->depthMapping == mjDB_ONETOZERO) {
+    glDepthFunc(GL_GEQUAL);
+  } else {
+    glDepthFunc(GL_LEQUAL);
+  }
   glDepthRange(0, 1);
   glAlphaFunc(GL_GEQUAL, 0.99f);
   glClearColor(0, 0, 0, 0);
-  glClearDepth(1);
+  if (con->depthMapping == mjDB_ONETOZERO) {
+    glClearDepth(0);
+  } else {
+    glClearDepth(1);
+  }
   glClearStencil(0);
   glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
 
@@ -600,6 +613,11 @@ static void setView(int view, mjrRect viewport, const mjvScene* scn, const mjrCo
   // set projection
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
+  if (con->depthMapping == mjDB_ONETOZERO) {
+    // account for GL_ZERO_TO_ONE and reverse Z
+    glTranslatef(0,0,0.5);
+    glScalef(1,1,-0.5);
+  }
   glFrustum(cam.frustum_center - halfwidth,
             cam.frustum_center + halfwidth,
             cam.frustum_bottom,
@@ -672,12 +690,25 @@ void mjr_render(mjrRect viewport, mjvScene* scn, const mjrContext* con) {
   float temp[4], headpos[3], forward[3], skyboxdst;
   float camProject[16], camView[16], lightProject[16], lightView[16];
   double clipplane[4];
-  float biasMatrix[16] = {
+  float biasMatrixOneToZero[16] = {
+    0.5f, 0.0f, 0.0f, 0.0f,
+    0.0f, 0.5f, 0.0f, 0.0f,
+    0.0f, 0.0f, 1.0f, 0.0f,
+    0.5f, 0.5f, 0.0f, 1.0f
+  };
+  float biasMatrixNegOneToOne[16] = {
     0.5f, 0.0f, 0.0f, 0.0f,
     0.0f, 0.5f, 0.0f, 0.0f,
     0.0f, 0.0f, 0.5f, 0.0f,
     0.5f, 0.5f, 0.5f, 1.0f
   };
+  float* biasMatrix;
+  if (con->depthMapping == mjDB_ONETOZERO) {
+    biasMatrix = biasMatrixOneToZero;
+  } else {
+    biasMatrix = biasMatrixNegOneToOne;
+  }
+
   float tempMatrix[16], textureMatrix[16];
   mjvGeom *thisgeom, tempgeom;
   mjvLight *thislight;
@@ -1025,6 +1056,11 @@ void mjr_render(mjrRect viewport, mjvScene* scn, const mjrContext* con) {
           // set projection: from light viewpoint
           glMatrixMode(GL_PROJECTION);
           glLoadIdentity();
+          if (con->depthMapping == mjDB_ONETOZERO) {
+            // account for GL_ZERO_TO_ONE and reverse Z
+            glTranslatef(0,0,0.5);
+            glScalef(1,1,-0.5);
+          }
           if (thislight->directional) {
             glOrtho(-con->shadowClip, con->shadowClip,
                     -con->shadowClip, con->shadowClip,

unity/Runtime/Bindings/MjBindings.cs

@@ -389,6 +389,14 @@ public enum mjtFramebuffer : int{
   mjFB_WINDOW = 0,
   mjFB_OFFSCREEN = 1,
 }
+public enum mjtDepthMapping : int{
+  mjDB_NEGONETOONE = 0,
+  mjDB_ONETOZERO = 1,
+}
+public enum mjtDepthPrecision : int{
+  mjDB_INT24 = 0,
+  mjDB_FLOAT32 = 1,
+}
 public enum mjtFontScale : int{
   mjFONTSCALE_50 = 50,
   mjFONTSCALE_100 = 100,