GPUTexture: Small refactor.

This includes a few modification:
 - The biggest one is call glActiveTexture before doing any call to
   glBindTexture for rendering purpose (uniform value depends on it).
   This is also better to know what's going on when rendering UI. So if
   there is missing UI elements because of this commit look for this first.
   This allows us to have "less calls" to glActiveTexture (I did not
   measure the final count) and less checks inside GPU_texture.

 - Remove use of GL_TEXTURE0 as a uniform value in a few places.

 - Be more strict and use BLI_assert for bad usage of GPU_texture functions.

 - Disable filtering for integer and stencil textures (not supported by
   OGL specs).

 - Replace bools inside GPUTexture by a bitflag supporting more options to
   identify texture types.

14 files changed, 120 insertions, 127 deletions

diff --git a/source/blender/blenfont/intern/blf_glyph.c b/source/blender/blenfont/intern/blf_glyph.c
index a7d52e96800..5a8691c9b4f 100644
--- a/source/blender/blenfont/intern/blf_glyph.c
+++ b/source/blender/blenfont/intern/blf_glyph.c
@@ -410,6 +410,8 @@ void blf_glyph_render(FontBLF *font, GlyphBLF *g, float x, float y)
 	if ((!g->width) || (!g->height))
 		return;
 
+	glActiveTexture(GL_TEXTURE0);
+
 	if (g->build_tex == 0) {
 		GlyphCacheBLF *gc = font->glyph_cache;
 
diff --git a/source/blender/draw/intern/draw_manager_texture.c b/source/blender/draw/intern/draw_manager_texture.c
index f3b4af7df1b..3a258954dbd 100644
--- a/source/blender/draw/intern/draw_manager_texture.c
+++ b/source/blender/draw/intern/draw_manager_texture.c
@@ -120,7 +120,7 @@ void drw_texture_set_parameters(GPUTexture *tex, DRWTextureFlag flags)
 	GPU_texture_bind(tex, 0);
 	if (flags & DRW_TEX_MIPMAP) {
 		GPU_texture_mipmap_mode(tex, true, flags & DRW_TEX_FILTER);
-		DRW_texture_generate_mipmaps(tex);
+		GPU_texture_generate_mipmap(tex);
 	}
 	else {
 		GPU_texture_filter_mode(tex, flags & DRW_TEX_FILTER);
diff --git a/source/blender/editors/interface/interface_icons.c b/source/blender/editors/interface/interface_icons.c
index 6f56576a208..f7cdb5cdc9c 100644
--- a/source/blender/editors/interface/interface_icons.c
+++ b/source/blender/editors/interface/interface_icons.c
@@ -1027,6 +1027,7 @@ static void icon_draw_texture(
 	y1 = iy * icongltex.invh;
 	y2 = (iy + ih) * icongltex.invh;
 
+	glActiveTexture(GL_TEXTURE0);
 	glBindTexture(GL_TEXTURE_2D, icongltex.id);
 	Gwn_VertFormat *format = immVertexFormat();
 	unsigned int pos = GWN_vertformat_attr_add(format, "pos", GWN_COMP_F32, 2, GWN_FETCH_FLOAT);
diff --git a/source/blender/editors/screen/glutil.c b/source/blender/editors/screen/glutil.c
index cd53655a0bb..cd875c73eda 100644
--- a/source/blender/editors/screen/glutil.c
+++ b/source/blender/editors/screen/glutil.c
@@ -198,6 +198,7 @@ void immDrawPixelsTexScaled_clipping(IMMDrawPixelsTexState *state,
 	glGetIntegerv(GL_UNPACK_ROW_LENGTH, &unpack_row_length);
 
 	glPixelStorei(GL_UNPACK_ROW_LENGTH, img_w);
+	glActiveTexture(GL_TEXTURE0);
 	glBindTexture(GL_TEXTURE_2D, texid);
 
 	/* don't want nasty border artifacts */
diff --git a/source/blender/editors/sculpt_paint/paint_cursor.c b/source/blender/editors/sculpt_paint/paint_cursor.c
index d2063d15ddf..6229b91a518 100644
--- a/source/blender/editors/sculpt_paint/paint_cursor.c
+++ b/source/blender/editors/sculpt_paint/paint_cursor.c
@@ -338,6 +338,7 @@ static int load_tex(Brush *br, ViewContext *vc, float zoom, bool col, bool prima
 		size = target->old_size;
 	}
 
+	glActiveTexture(GL_TEXTURE0);
 	glBindTexture(GL_TEXTURE_2D, target->overlay_texture);
 
 	if (refresh) {
@@ -464,6 +465,7 @@ static int load_tex_cursor(Brush *br, ViewContext *vc, float zoom)
 		size = cursor_snap.size;
 	}
 
+	glActiveTexture(GL_TEXTURE0);
 	glBindTexture(GL_TEXTURE_2D, cursor_snap.overlay_texture);
 
 	if (refresh) {
@@ -767,7 +769,7 @@ static void paint_draw_cursor_overlay(UnifiedPaintSettings *ups, Brush *brush,
 		/* draw textured quad */
 
 		/* draw textured quad */
-		immUniform1i("image", GL_TEXTURE0);
+		immUniform1i("image", 0);
 
 		immBegin(GWN_PRIM_TRI_FAN, 4);
 		immAttrib2f(texCoord, 0.0f, 0.0f);
diff --git a/source/blender/editors/space_clip/clip_draw.c b/source/blender/editors/space_clip/clip_draw.c
index 96968a14883..5962bfe33f3 100644
--- a/source/blender/editors/space_clip/clip_draw.c
+++ b/source/blender/editors/space_clip/clip_draw.c
@@ -1131,6 +1131,7 @@ static void draw_plane_marker_image(Scene *scene,
 
 			glGenTextures(1, (GLuint *)&texid);
 
+			glActiveTexture(GL_TEXTURE0);
 			glBindTexture(GL_TEXTURE_2D, texid);
 
 			glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
@@ -1148,7 +1149,7 @@ static void draw_plane_marker_image(Scene *scene,
 
 			immBindBuiltinProgram(GPU_SHADER_2D_IMAGE_COLOR);
 			immUniformColor4f(1.0f, 1.0f, 1.0f, plane_track->image_opacity);
-			immUniform1i("image", GL_TEXTURE0);
+			immUniform1i("image", 0);
 
 			immBegin(GWN_PRIM_TRI_FAN, 4);
 
diff --git a/source/blender/editors/space_sequencer/sequencer_draw.c b/source/blender/editors/space_sequencer/sequencer_draw.c
index f6d18ad0a52..8e5863fd514 100644
--- a/source/blender/editors/space_sequencer/sequencer_draw.c
+++ b/source/blender/editors/space_sequencer/sequencer_draw.c
@@ -1309,6 +1309,7 @@ void draw_image_seq(const bContext *C, Scene *scene, ARegion *ar, SpaceSeq *sseq
 
 	glGenTextures(1, (GLuint *)&texid);
 
+	glActiveTexture(GL_TEXTURE0);
 	glBindTexture(GL_TEXTURE_2D, texid);
 
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
@@ -1322,7 +1323,7 @@ void draw_image_seq(const bContext *C, Scene *scene, ARegion *ar, SpaceSeq *sseq
 	if (!glsl_used) {
 		immBindBuiltinProgram(GPU_SHADER_2D_IMAGE_COLOR);
 		immUniformColor3f(1.0f, 1.0f, 1.0f);
-		immUniform1i("image", GL_TEXTURE0);
+		immUniform1i("image", 0);
 	}
 
 	immBegin(GWN_PRIM_TRI_FAN, 4);
diff --git a/source/blender/editors/space_view3d/drawobject.c b/source/blender/editors/space_view3d/drawobject.c
index ea92f18f714..f46d3c500bc 100644
--- a/source/blender/editors/space_view3d/drawobject.c
+++ b/source/blender/editors/space_view3d/drawobject.c
@@ -755,8 +755,6 @@ static void draw_empty_image(Object *ob, const short dflag, const unsigned char
 		immEnd();
 
 		immUnbindProgram();
-
-		glBindTexture(GL_TEXTURE_2D, 0); /* necessary? */
 	}
 
 	/* Draw the image outline */
diff --git a/source/blender/gpu/GPU_texture.h b/source/blender/gpu/GPU_texture.h
index 0fde0edcf2b..72e3859a5a8 100644
--- a/source/blender/gpu/GPU_texture.h
+++ b/source/blender/gpu/GPU_texture.h
@@ -196,10 +196,12 @@ void GPU_texture_framebuffer_set(GPUTexture *tex, struct GPUFrameBuffer *fb, int
 int GPU_texture_target(const GPUTexture *tex);
 int GPU_texture_width(const GPUTexture *tex);
 int GPU_texture_height(const GPUTexture *tex);
-int GPU_texture_format(const GPUTexture *tex);
+GPUTextureFormat GPU_texture_format(const GPUTexture *tex);
 int GPU_texture_samples(const GPUTexture *tex);
+bool GPU_texture_cube(const GPUTexture *tex);
 bool GPU_texture_depth(const GPUTexture *tex);
 bool GPU_texture_stencil(const GPUTexture *tex);
+bool GPU_texture_integer(const GPUTexture *tex);
 int GPU_texture_opengl_bindcode(const GPUTexture *tex);
 
 #ifdef __cplusplus
diff --git a/source/blender/gpu/intern/gpu_texture.c b/source/blender/gpu/intern/gpu_texture.c
index bd25dd03f13..1aee994f29e 100644
--- a/source/blender/gpu/intern/gpu_texture.c
+++ b/source/blender/gpu/intern/gpu_texture.c
@@ -48,6 +48,19 @@ static struct GPUTextureGlobal {
 	GPUTexture *invalid_tex_3D;
 } GG = {NULL, NULL, NULL};
 
+typedef enum GPUTextureFormatFlag{
+	GPU_FORMAT_DEPTH     = (1 << 0),
+	GPU_FORMAT_STENCIL   = (1 << 1),
+	GPU_FORMAT_INTEGER   = (1 << 2),
+	GPU_FORMAT_FLOAT     = (1 << 3),
+
+	GPU_FORMAT_1D        = (1 << 10),
+	GPU_FORMAT_2D        = (1 << 11),
+	GPU_FORMAT_3D        = (1 << 12),
+	GPU_FORMAT_CUBE      = (1 << 13),
+	GPU_FORMAT_ARRAY     = (1 << 14),
+} GPUTextureFormatFlag;
+
 /* GPUTexture */
 struct GPUTexture {
 	int w, h, d;        /* width/height/depth */
@@ -59,13 +72,12 @@ struct GPUTexture {
 	GLuint bindcode;    /* opengl identifier for texture */
 	int fromblender;    /* we got the texture from Blender */
 
+	GPUTextureFormatFlag format_flag;
 	GPUFrameBuffer *fb; /* GPUFramebuffer this texture is attached to */
 	int fb_attachment;  /* slot the texture is attached to */
-	bool depth;         /* is a depth texture? */
-	bool stencil;       /* is a stencil texture? */
 
 	unsigned int bytesize; /* number of byte for one pixel */
-	int format;         /* GPUTextureFormat */
+	GPUTextureFormat format;
 	int components;     /* number of color/alpha channels */
 	int samples;        /* number of samples for multisamples textures. 0 if not multisample target */
 };
@@ -114,30 +126,26 @@ unsigned int GPU_texture_memory_usage_get(void)
 
 static GLenum gpu_texture_get_format(
         int components, GPUTextureFormat data_type,
-        GLenum *format, GLenum *data_format, bool *is_depth, bool *is_stencil, unsigned int *bytesize)
+        GLenum *format, GLenum *data_format, GPUTextureFormatFlag *format_flag, unsigned int *bytesize)
 {
 	if (ELEM(data_type, GPU_DEPTH_COMPONENT24,
 	                    GPU_DEPTH_COMPONENT16,
 	                    GPU_DEPTH_COMPONENT32F))
 	{
-		*is_depth = true;
-		*is_stencil = false;
+		*format_flag |= GPU_FORMAT_DEPTH;
 		*data_format = GL_FLOAT;
 		*format = GL_DEPTH_COMPONENT;
 	}
 	else if (data_type == GPU_DEPTH24_STENCIL8) {
-		*is_depth = true;
-		*is_stencil = true;
+		*format_flag |= GPU_FORMAT_DEPTH | GPU_FORMAT_STENCIL;
 		*data_format = GL_UNSIGNED_INT_24_8;
 		*format = GL_DEPTH_STENCIL;
 	}
 	else {
-		*is_depth = false;
-		*is_stencil = false;
-
 		/* Integer formats */
 		if (ELEM(data_type, GPU_RG16I, GPU_R16I)) {
 			*data_format = GL_INT;
+			*format_flag |= GPU_FORMAT_INTEGER;
 
 			switch (components) {
 				case 1: *format = GL_RED_INTEGER; break;
@@ -149,6 +157,7 @@ static GLenum gpu_texture_get_format(
 		}
 		else {
 			*data_format = GL_FLOAT;
+			*format_flag |= GPU_FORMAT_FLOAT;
 
 			switch (components) {
 				case 1: *format = GL_RED; break;
@@ -349,6 +358,7 @@ static GPUTexture *GPU_texture_create_nD(
 	tex->fb_attachment = -1;
 	tex->format = data_type;
 	tex->components = components;
+	tex->format_flag = 0;
 
 	if (n == 2) {
 		if (d == 0)
@@ -375,7 +385,8 @@ static GPUTexture *GPU_texture_create_nD(
 		tex->target = GL_TEXTURE_2D_MULTISAMPLE;
 
 	GLenum format, internalformat, data_format;
-	internalformat = gpu_texture_get_format(components, data_type, &format, &data_format, &tex->depth, &tex->stencil, &tex->bytesize);
+	internalformat = gpu_texture_get_format(components, data_type, &format, &data_format,
+	                                        &tex->format_flag, &tex->bytesize);
 
 	gpu_texture_memory_footprint_add(tex);
 
@@ -391,7 +402,6 @@ static GPUTexture *GPU_texture_create_nD(
 		return NULL;
 	}
 
-	tex->number = 0;
 	glBindTexture(tex->target, tex->bindcode);
 
 	/* Check if texture fit in VRAM */
@@ -450,17 +460,23 @@ static GPUTexture *GPU_texture_create_nD(
 		MEM_freeN(rescaled_fpixels);
 
 	/* Texture Parameters */
-	if (tex->depth) {
+	if (GPU_texture_stencil(tex) || /* Does not support filtering */
+		GPU_texture_integer(tex) || /* Does not support filtering */
+		GPU_texture_depth(tex))
+	{
 		glTexParameteri(tex->target_base, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
-		glTexParameteri(tex->target_base, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-		glTexParameteri(tex->target_base, GL_TEXTURE_COMPARE_MODE, GL_NONE);
-		glTexParameteri(tex->target_base, GL_TEXTURE_COMPARE_FUNC, GL_LEQUAL);
+		glTexParameteri(tex->target_base, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 	}
 	else {
 		glTexParameteri(tex->target_base, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 		glTexParameteri(tex->target_base, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 	}
 
+	if (GPU_texture_depth(tex)) {
+		glTexParameteri(tex->target_base, GL_TEXTURE_COMPARE_MODE, GL_NONE);
+		glTexParameteri(tex->target_base, GL_TEXTURE_COMPARE_FUNC, GL_LEQUAL);
+	}
+
 	glTexParameteri(tex->target_base, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 	if (n > 1) {
 		glTexParameteri(tex->target_base, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
@@ -469,7 +485,7 @@ static GPUTexture *GPU_texture_create_nD(
 		glTexParameteri(tex->target_base, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
 	}
 
-	GPU_texture_unbind(tex);
+	glBindTexture(tex->target, 0);
 
 	return tex;
 }
@@ -493,6 +509,7 @@ static GPUTexture *GPU_texture_cube_create(
 	tex->fb_attachment = -1;
 	tex->format = data_type;
 	tex->components = components;
+	tex->format_flag = GPU_FORMAT_CUBE;
 
 	if (d == 0) {
 		tex->target_base = tex->target = GL_TEXTURE_CUBE_MAP;
@@ -502,7 +519,8 @@ static GPUTexture *GPU_texture_cube_create(
 		// tex->target_base = tex->target = GL_TEXTURE_CUBE_MAP_ARRAY;
 	}
 
-	internalformat = gpu_texture_get_format(components, data_type, &format, &data_format, &tex->depth, &tex->stencil, &tex->bytesize);
+	internalformat = gpu_texture_get_format(components, data_type, &format, &data_format,
+	                                        &tex->format_flag, &tex->bytesize);
 
 	gpu_texture_memory_footprint_add(tex);
 
@@ -518,7 +536,6 @@ static GPUTexture *GPU_texture_cube_create(
 		return NULL;
 	}
 
-	tex->number = 0;
 	glBindTexture(tex->target, tex->bindcode);
 
 	/* Upload Texture */
@@ -530,22 +547,28 @@ static GPUTexture *GPU_texture_cube_create(
 	glTexImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, 0, internalformat, tex->w, tex->h, 0, format, data_format, fpixels_nz);
 
 	/* Texture Parameters */
-	if (tex->depth) {
+	if (GPU_texture_stencil(tex) || /* Does not support filtering */
+	    GPU_texture_integer(tex) || /* Does not support filtering */
+	    GPU_texture_depth(tex))
+	{
 		glTexParameteri(tex->target_base, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
-		glTexParameteri(tex->target_base, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-		glTexParameteri(tex->target_base, GL_TEXTURE_COMPARE_MODE, GL_NONE);
-		glTexParameteri(tex->target_base, GL_TEXTURE_COMPARE_FUNC, GL_LEQUAL);
+		glTexParameteri(tex->target_base, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 	}
 	else {
 		glTexParameteri(tex->target_base, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 		glTexParameteri(tex->target_base, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 	}
 
+	if (GPU_texture_depth(tex)) {
+		glTexParameteri(tex->target_base, GL_TEXTURE_COMPARE_MODE, GL_NONE);
+		glTexParameteri(tex->target_base, GL_TEXTURE_COMPARE_FUNC, GL_LEQUAL);
+	}
+
 	glTexParameteri(tex->target_base, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 	glTexParameteri(tex->target_base, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 	glTexParameteri(tex->target_base, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
 
-	GPU_texture_unbind(tex);
+	glBindTexture(tex->target, 0);
 
 	return tex;
 }
@@ -751,7 +774,8 @@ void GPU_texture_update(GPUTexture *tex, const float *pixels)
 	BLI_assert(tex->components > -1);
 
 	GLenum format, data_format;
-	gpu_texture_get_format(tex->components, tex->format, &format, &data_format, &tex->depth, &tex->stencil, &tex->bytesize);
+	gpu_texture_get_format(tex->components, tex->format, &format, &data_format,
+	                       &tex->format_flag, &tex->bytesize);
 
 	glBindTexture(tex->target, tex->bindcode);
 
@@ -809,9 +833,10 @@ void GPU_invalid_tex_free(void)
 		GPU_texture_free(GG.invalid_tex_3D);
 }
 
-
 void GPU_texture_bind(GPUTexture *tex, int number)
 {
+	BLI_assert(number >= 0);
+
 	if (number >= GPU_max_textures()) {
 		fprintf(stderr, "Not enough texture slots.\n");
 		return;
@@ -823,41 +848,24 @@ void GPU_texture_bind(GPUTexture *tex, int number)
 		}
 	}
 
-	if (number < 0)
-		return;
-
-	if (number != 0)
-		glActiveTexture(GL_TEXTURE0 + number);
+	glActiveTexture(GL_TEXTURE0 + number);
 
 	if (tex->bindcode != 0)
 		glBindTexture(tex->target, tex->bindcode);
 	else
 		GPU_invalid_tex_bind(tex->target_base);
 
-	if (number != 0)
-		glActiveTexture(GL_TEXTURE0);
-
 	tex->number = number;
 }
 
 void GPU_texture_unbind(GPUTexture *tex)
 {
-	if (tex->number >= GPU_max_textures()) {
-		fprintf(stderr, "Not enough texture slots.\n");
-		return;
-	}
-
 	if (tex->number == -1)
 		return;
 
-	if (tex->number != 0)
-		glActiveTexture(GL_TEXTURE0 + tex->number);
-
+	glActiveTexture(GL_TEXTURE0 + tex->number);
 	glBindTexture(tex->target, 0);
 
-	if (tex->number != 0)
-		glActiveTexture(GL_TEXTURE0);
-
 	tex->number = -1;
 }
 
@@ -866,114 +874,79 @@ int GPU_texture_bound_number(GPUTexture *tex)
 	return tex->number;
 }
 
+#define WARN_NOT_BOUND(_tex) do { \
+	if (_tex->number == -1) { \
+		fprintf(stderr, "Warning : Trying to set parameter on a texture not bound.\n"); \
+		BLI_assert(0); \
+		return; \
+	} \
+} while (0);
+
 void GPU_texture_generate_mipmap(GPUTexture *tex)
 {
-	if (tex->number >= GPU_max_textures()) {
-		fprintf(stderr, "Not enough texture slots.\n");
-		return;
-	}
-
-	if (tex->number == -1)
-		return;
-
-	if (tex->number != 0)
-		glActiveTexture(GL_TEXTURE0 + tex->number);
+	WARN_NOT_BOUND(tex);
 
+	glActiveTexture(GL_TEXTURE0 + tex->number);
 	glGenerateMipmap(tex->target_base);
-
-	if (tex->number != 0)
-		glActiveTexture(GL_TEXTURE0);
 }
 
 void GPU_texture_compare_mode(GPUTexture *tex, bool use_compare)
 {
-	if (tex->number >= GPU_max_textures()) {
-		fprintf(stderr, "Not enough texture slots.\n");
-		return;
-	}
+	WARN_NOT_BOUND(tex);
 
-	if (tex->number == -1)
+	/* Could become an assertion ? (fclem) */
+	if (!GPU_texture_depth(tex))
 		return;
 
-	if (tex->number != 0)
-		glActiveTexture(GL_TEXTURE0 + tex->number);
+	GLenum mode = (use_compare) ? GL_COMPARE_REF_TO_TEXTURE : GL_NONE;
 
-	/* TODO viewport: use GL_COMPARE_REF_TO_TEXTURE after we switch to core profile */
-	if (tex->depth)
-		glTexParameteri(tex->target_base, GL_TEXTURE_COMPARE_MODE, use_compare ? GL_COMPARE_R_TO_TEXTURE : GL_NONE);
-
-	if (tex->number != 0)
-		glActiveTexture(GL_TEXTURE0);
+	glActiveTexture(GL_TEXTURE0 + tex->number);
+	glTexParameteri(tex->target_base, GL_TEXTURE_COMPARE_MODE, mode);
 }
 
 void GPU_texture_filter_mode(GPUTexture *tex, bool use_filter)
 {
-	if (tex->number >= GPU_max_textures()) {
-		fprintf(stderr, "Not enough texture slots.\n");
-		return;
-	}
+	WARN_NOT_BOUND(tex);
 
-	if (tex->number == -1)
-		return;
+	/* Stencil and integer format does not support filtering. */
+	BLI_assert(!use_filter || !(GPU_texture_stencil(tex) || GPU_texture_integer(tex)));
 
-	if (tex->number != 0)
-		glActiveTexture(GL_TEXTURE0 + tex->number);
+	GLenum filter = (use_filter) ? GL_LINEAR : GL_NEAREST;
 
-	GLenum filter = use_filter ? GL_LINEAR : GL_NEAREST;
+	glActiveTexture(GL_TEXTURE0 + tex->number);
 	glTexParameteri(tex->target_base, GL_TEXTURE_MAG_FILTER, filter);
 	glTexParameteri(tex->target_base, GL_TEXTURE_MIN_FILTER, filter);
-
-	if (tex->number != 0)
-		glActiveTexture(GL_TEXTURE0);
 }
 
 void GPU_texture_mipmap_mode(GPUTexture *tex, bool use_mipmap, bool use_filter)
 {
-	if (tex->number >= GPU_max_textures()) {
-		fprintf(stderr, "Not enough texture slots.\n");
-		return;
-	}
-
-	if (tex->number == -1)
-		return;
+	WARN_NOT_BOUND(tex);
 
-	if (tex->number != 0)
-		glActiveTexture(GL_TEXTURE0 + tex->number);
+	/* Stencil and integer format does not support filtering. */
+	BLI_assert((!use_filter && !use_mipmap) || !(GPU_texture_stencil(tex) || GPU_texture_integer(tex)));
 
+	GLenum filter = (use_filter) ? GL_LINEAR : GL_NEAREST;
 	GLenum mipmap = (use_filter)
-	       ? use_mipmap ? GL_LINEAR_MIPMAP_LINEAR : GL_LINEAR
-	       : use_mipmap ? GL_NEAREST_MIPMAP_LINEAR : GL_NEAREST;
-	glTexParameteri(tex->target_base, GL_TEXTURE_MIN_FILTER, mipmap);
+	       ? (use_mipmap) ? GL_LINEAR_MIPMAP_LINEAR : GL_LINEAR
+	       : (use_mipmap) ? GL_NEAREST_MIPMAP_LINEAR : GL_NEAREST;
 
-	GLenum filter = use_filter ? GL_LINEAR : GL_NEAREST;
+	glActiveTexture(GL_TEXTURE0 + tex->number);
+	glTexParameteri(tex->target_base, GL_TEXTURE_MIN_FILTER, mipmap);
 	glTexParameteri(tex->target_base, GL_TEXTURE_MAG_FILTER, filter);
-
-	if (tex->number != 0)
-		glActiveTexture(GL_TEXTURE0);
 }
 
 void GPU_texture_wrap_mode(GPUTexture *tex, bool use_repeat)
 {
-	if (tex->number >= GPU_max_textures()) {
-		fprintf(stderr, "Not enough texture slots.\n");
-		return;
-	}
-
-	if (tex->number == -1)
-		return;
+	WARN_NOT_BOUND(tex);
 
-	if (tex->number != 0)
-		glActiveTexture(GL_TEXTURE0 + tex->number);
+	GLenum repeat = (use_repeat) ? GL_REPEAT : GL_CLAMP_TO_EDGE;
 
-	GLenum repeat = use_repeat ? GL_REPEAT : GL_CLAMP_TO_EDGE;
+	glActiveTexture(GL_TEXTURE0 + tex->number);
 	glTexParameteri(tex->target_base, GL_TEXTURE_WRAP_S, repeat);
 	if (tex->target_base != GL_TEXTURE_1D)
 		glTexParameteri(tex->target_base, GL_TEXTURE_WRAP_T, repeat);
 	if (tex->target_base == GL_TEXTURE_3D)
 		glTexParameteri(tex->target_base, GL_TEXTURE_WRAP_R, repeat);
-
-	if (tex->number != 0)
-		glActiveTexture(GL_TEXTURE0);
 }
 
 void GPU_texture_free(GPUTexture *tex)
@@ -1015,7 +988,7 @@ int GPU_texture_height(const GPUTexture *tex)
 	return tex->h;
 }
 
-int GPU_texture_format(const GPUTexture *tex)
+GPUTextureFormat GPU_texture_format(const GPUTexture *tex)
 {
 	return tex->format;
 }
@@ -1027,12 +1000,22 @@ int GPU_texture_samples(const GPUTexture *tex)
 
 bool GPU_texture_depth(const GPUTexture *tex)
 {
-	return tex->depth;
+	return (tex->format_flag & GPU_FORMAT_DEPTH) != 0;
 }
 
 bool GPU_texture_stencil(const GPUTexture *tex)
 {
-	return tex->stencil;
+	return (tex->format_flag & GPU_FORMAT_STENCIL) != 0;
+}
+
+bool GPU_texture_integer(const GPUTexture *tex)
+{
+	return (tex->format_flag & GPU_FORMAT_INTEGER) != 0;
+}
+
+bool GPU_texture_cube(const GPUTexture *tex)
+{
+	return (tex->format_flag & GPU_FORMAT_CUBE) != 0;
 }
 
 int GPU_texture_opengl_bindcode(const GPUTexture *tex)
diff --git a/source/blender/gpu/intern/gpu_viewport.c b/source/blender/gpu/intern/gpu_viewport.c
index 2ad89bd1345..9d60afe372a 100644
--- a/source/blender/gpu/intern/gpu_viewport.c
+++ b/source/blender/gpu/intern/gpu_viewport.c
@@ -407,7 +407,7 @@ static void gpu_viewport_default_fb_create(GPUViewport *viewport)
 		/* Define texture parameters */
 		GPU_texture_bind(dtxl->depth, 0);
 		GPU_texture_compare_mode(dtxl->depth, false);
-		GPU_texture_filter_mode(dtxl->depth, true);
+		GPU_texture_filter_mode(dtxl->depth, false);
 		GPU_texture_unbind(dtxl->depth);
 	}
 	else {
diff --git a/source/blender/windowmanager/intern/wm_draw.c b/source/blender/windowmanager/intern/wm_draw.c
index 4a6bc2ded28..cfd3291293c 100644
--- a/source/blender/windowmanager/intern/wm_draw.c
+++ b/source/blender/windowmanager/intern/wm_draw.c
@@ -505,8 +505,6 @@ void wm_triple_draw_textures(wmWindow *win, wmDrawTriple *triple, float alpha)
 	immUnbindProgram();
 
 	glBindTexture(GL_TEXTURE_2D, 0);
-	if (activeTex != 0)
-		glActiveTexture(GL_TEXTURE0);
 }
 
 static void wm_triple_copy_textures(wmWindow *win, wmDrawTriple *triple)
diff --git a/source/blender/windowmanager/intern/wm_operators.c b/source/blender/windowmanager/intern/wm_operators.c
index 53098ea58b2..fb8130f8954 100644
--- a/source/blender/windowmanager/intern/wm_operators.c
+++ b/source/blender/windowmanager/intern/wm_operators.c
@@ -2504,6 +2504,7 @@ static void radial_control_set_tex(RadialControl *rc)
 				glBindTexture(GL_TEXTURE_2D, rc->gltex);
 				glTexImage2D(GL_TEXTURE_2D, 0, GL_R8, ibuf->x, ibuf->y, 0,
 				             GL_RED, GL_FLOAT, ibuf->rect_float);
+				glBindTexture(GL_TEXTURE_2D, 0);
 				MEM_freeN(ibuf->rect_float);
 				MEM_freeN(ibuf);
 			}
@@ -2544,6 +2545,7 @@ static void radial_control_paint_tex(RadialControl *rc, float radius, float alph
 
 		unsigned int texCoord = GWN_vertformat_attr_add(format, "texCoord", GWN_COMP_F32, 2, GWN_FETCH_FLOAT);
 
+		glActiveTexture(GL_TEXTURE0);
 		glBindTexture(GL_TEXTURE_2D, rc->gltex);
 
 		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
@@ -2555,7 +2557,7 @@ static void radial_control_paint_tex(RadialControl *rc, float radius, float alph
 		immBindBuiltinProgram(GPU_SHADER_2D_IMAGE_MASK_UNIFORM_COLOR);
 
 		immUniformColor3fvAlpha(col, alpha);
-		immUniform1i("image", GL_TEXTURE0);
+		immUniform1i("image", 0);
 
 		/* set up rotation if available */
 		if (rc->rot_prop) {
diff --git a/source/blender/windowmanager/intern/wm_stereo.c b/source/blender/windowmanager/intern/wm_stereo.c
index b70769b2d51..b52fc4ae213 100644
--- a/source/blender/windowmanager/intern/wm_stereo.c
+++ b/source/blender/windowmanager/intern/wm_stereo.c
@@ -204,6 +204,7 @@ static void wm_method_draw_stereo3d_sidebyside(wmWindow *win)
 	unsigned int pos = GWN_vertformat_attr_add(format, "pos", GWN_COMP_F32, 2, GWN_FETCH_FLOAT);
 
 	immBindBuiltinProgram(GPU_SHADER_2D_IMAGE_ALPHA);
+	glActiveTexture(GL_TEXTURE0);
 
 	for (view = 0; view < 2; view ++) {
 		drawdata = BLI_findlink(&win->drawdata, (view * 2) + 1);
@@ -266,6 +267,7 @@ static void wm_method_draw_stereo3d_topbottom(wmWindow *win)
 	unsigned int pos = GWN_vertformat_attr_add(format, "pos", GWN_COMP_F32, 2, GWN_FETCH_FLOAT);
 
 	immBindBuiltinProgram(GPU_SHADER_2D_IMAGE_ALPHA);
+	glActiveTexture(GL_TEXTURE0);
 
 	for (view = 0; view < 2; view ++) {
 		drawdata = BLI_findlink(&win->drawdata, (view * 2) + 1);