[v4,4/7] libcamera: egl: Add updateTexture2D
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Message ID 20260706110120.2509826-5-bryan.odonoghue@linaro.org
State New
Headers show
Series
  • libcamera: software_isp: gpu: Add go faster stripes
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Commit Message

Bryan O'Donoghue July 6, 2026, 11:01 a.m. UTC 
The internet box tells me that glTextSubImage2D lets us update a texture's
data only, instead of recreating the texture and uploading data.

This is a smallish optimisation but we are hunting for every possible cycle
and watt so add the routine as precursor to using it in-place of
createTexture2D on every upload cycle.

Reviewed-by: Robert Mader <robert.mader@collabora.com>
Reviewed-by: Milan Zamazal <mzamazal@redhat.com>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
---
 include/libcamera/internal/egl.h |  1 +
 src/libcamera/egl.cpp            | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)

Patch
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diff --git a/include/libcamera/internal/egl.h b/include/libcamera/internal/egl.h
index 1955d09c5..9b4261c55 100644
--- a/include/libcamera/internal/egl.h
+++ b/include/libcamera/internal/egl.h
@@ -108,6 +108,7 @@  public:
 	int createInputDMABufTexture2D(eGLImage &eglImage, int fd);
 	int createOutputDMABufTexture2D(eGLImage &eglImage, int fd);
 	void createTexture2D(eGLImage &eglImage, void *data);
+	void updateTexture2D(eGLImage &eglImage, void *data);
 	void createOutputTexture2D(eGLImage &eglImage);
 
 	int attachTextureToFBO(eGLImage &eglImage);
diff --git a/src/libcamera/egl.cpp b/src/libcamera/egl.cpp
index c1b5514b6..b91f9096a 100644
--- a/src/libcamera/egl.cpp
+++ b/src/libcamera/egl.cpp
@@ -329,6 +329,24 @@  bool eGL::isAvailable()
 	return true;
 }
 
+/**
+ * \brief Update a 2D texture already created
+ * \param[in,out] eglImage EGL image to associate with the texture
+ * \param[data] Data to update the texture with
+ *
+ * Updates a 2D texture in VRAM.
+ */
+void eGL::updateTexture2D(eGLImage &eglImage, void *data)
+{
+	ASSERT(tid_ == Thread::currentId());
+
+	glActiveTexture(eglImage.texture_unit_);
+	glBindTexture(GL_TEXTURE_2D, eglImage.texture_);
+
+	// Update an already existing texture
+	glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, eglImage.width_, eglImage.height_, eglImage.format_, GL_UNSIGNED_BYTE, data);
+}
+
 /**
  * \brief Create a 2D texture attached to an FBO for render-to-texture
  * \param[in,out] eglImage EGL image to associate with the texture